[vm/concurrency] Remove --(no-)enable-isolate-groups flag usage in tests

This is a preparation CL to remove the --enable-isolate-groups flag in
the VM.

The following tests were only running in --no-enable-isolate-groups and
are therefore obsolete now:

  - runtime/tests/vm/dart/regress_47468_test.dart
  - runtime/tests/vm/dart_2/regress_47468_test.dart
  - tests/lib/isolate/illegal_msg_function_test.dart
  - tests/lib_2/isolate/illegal_msg_function_test.dart

TEST=Changes tests only.

Change-Id: I6257cb667eebca66a649614d3010139dd2cdd3ab
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/219100
Reviewed-by: Alexander Aprelev <aam@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
diff --git a/benchmarks/IsolateFibonacci/dart/IsolateFibonacci.dart b/benchmarks/IsolateFibonacci/dart/IsolateFibonacci.dart
index 84b7572..4af3028 100644
--- a/benchmarks/IsolateFibonacci/dart/IsolateFibonacci.dart
+++ b/benchmarks/IsolateFibonacci/dart/IsolateFibonacci.dart
@@ -34,8 +34,7 @@
   final rpRun = ReceivePort();
   final int nWarmup = 17; // enough runs to trigger optimized compilation
   final int nWarmupFactorial = 2584;
-  // With --enable-isolate-groups runs for about 8 seconds.
-  // Should not be run witout --enable-isolate-groups as it would be too slow.
+  // Runs for about 8 seconds.
   final int n = 21;
   final int nFactorial = 17711;
   final beforeRss = ProcessInfo.currentRss;
@@ -48,8 +47,7 @@
   final watch = Stopwatch();
   watch.start();
 
-  // For the benefit of enable-isolate-groups configuration, warm up target
-  // isolate code by running couple iterations in the main isolate.
+  // Warm up code by running a couple iterations in the main isolate.
   await Isolate.spawn(fibonacciRecursive, [rpWarmup.sendPort, nWarmup]);
   Expect.equals(nWarmupFactorial, await rpWarmup.first);
 
@@ -60,7 +58,7 @@
 
   final done = watch.elapsedMicroseconds;
 
-  print('IsolateFibonacci_$n.Calculation(RunTimeRaw): ${done-warmup} us.');
-  print('IsolateFibonacci_$n.DeltaPeak(MemoryUse): ${maxRss-beforeRss}');
+  print('IsolateFibonacci_$n.Calculation(RunTimeRaw): ${done - warmup} us.');
+  print('IsolateFibonacci_$n.DeltaPeak(MemoryUse): ${maxRss - beforeRss}');
   rssTimer.cancel();
 }
diff --git a/benchmarks/IsolateFibonacci/dart2/IsolateFibonacci.dart b/benchmarks/IsolateFibonacci/dart2/IsolateFibonacci.dart
index 84b7572..4af3028 100644
--- a/benchmarks/IsolateFibonacci/dart2/IsolateFibonacci.dart
+++ b/benchmarks/IsolateFibonacci/dart2/IsolateFibonacci.dart
@@ -34,8 +34,7 @@
   final rpRun = ReceivePort();
   final int nWarmup = 17; // enough runs to trigger optimized compilation
   final int nWarmupFactorial = 2584;
-  // With --enable-isolate-groups runs for about 8 seconds.
-  // Should not be run witout --enable-isolate-groups as it would be too slow.
+  // Runs for about 8 seconds.
   final int n = 21;
   final int nFactorial = 17711;
   final beforeRss = ProcessInfo.currentRss;
@@ -48,8 +47,7 @@
   final watch = Stopwatch();
   watch.start();
 
-  // For the benefit of enable-isolate-groups configuration, warm up target
-  // isolate code by running couple iterations in the main isolate.
+  // Warm up code by running a couple iterations in the main isolate.
   await Isolate.spawn(fibonacciRecursive, [rpWarmup.sendPort, nWarmup]);
   Expect.equals(nWarmupFactorial, await rpWarmup.first);
 
@@ -60,7 +58,7 @@
 
   final done = watch.elapsedMicroseconds;
 
-  print('IsolateFibonacci_$n.Calculation(RunTimeRaw): ${done-warmup} us.');
-  print('IsolateFibonacci_$n.DeltaPeak(MemoryUse): ${maxRss-beforeRss}');
+  print('IsolateFibonacci_$n.Calculation(RunTimeRaw): ${done - warmup} us.');
+  print('IsolateFibonacci_$n.DeltaPeak(MemoryUse): ${maxRss - beforeRss}');
   rssTimer.cancel();
 }
diff --git a/benchmarks/IsolateSpawnMemory/dart/IsolateSpawnMemory.dart b/benchmarks/IsolateSpawnMemory/dart/IsolateSpawnMemory.dart
index 1f7b009..0160c03 100644
--- a/benchmarks/IsolateSpawnMemory/dart/IsolateSpawnMemory.dart
+++ b/benchmarks/IsolateSpawnMemory/dart/IsolateSpawnMemory.dart
@@ -158,16 +158,6 @@
 }
 
 // Returns the set of isolate groups for which we should count the heap usage.
-//
-// We have two cases
-//
-//   a) --enable-isolate-groups: All isolates will be within the same isolate
-//   group.
-//
-//   b) --no-enable-isolate-groups: All isolates will be within their own,
-//   separate isolate group.
-//
-// In both cases we want to sum up the heap sizes of all isolate groups.
 Future<List<String>> getGroupIds(vm_service.VmService vmService) async {
   final groupIds = <String>{};
   final vm = await vmService.getVM();
diff --git a/benchmarks/IsolateSpawnMemory/dart2/IsolateSpawnMemory.dart b/benchmarks/IsolateSpawnMemory/dart2/IsolateSpawnMemory.dart
index 115e705..28fee38 100644
--- a/benchmarks/IsolateSpawnMemory/dart2/IsolateSpawnMemory.dart
+++ b/benchmarks/IsolateSpawnMemory/dart2/IsolateSpawnMemory.dart
@@ -160,16 +160,6 @@
 }
 
 // Returns the set of isolate groups for which we should count the heap usage.
-//
-// We have two cases
-//
-//   a) --enable-isolate-groups: All isolates will be within the same isolate
-//   group.
-//
-//   b) --no-enable-isolate-groups: All isolates will be within their own,
-//   separate isolate group.
-//
-// In both cases we want to sum up the heap sizes of all isolate groups.
 Future<List<String>> getGroupIds(vm_service.VmService vmService) async {
   final groupIds = <String>{};
   final vm = await vmService.getVM();
diff --git a/pkg/vm_service/test/mark_main_isolate_as_system_isolate_test.dart b/pkg/vm_service/test/mark_main_isolate_as_system_isolate_test.dart
index fb97b82..6219ebf 100644
--- a/pkg/vm_service/test/mark_main_isolate_as_system_isolate_test.dart
+++ b/pkg/vm_service/test/mark_main_isolate_as_system_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:developer';
 import 'dart:io';
 import 'dart:isolate';
diff --git a/runtime/observatory/tests/service/break_on_function_child_isolate_test.dart b/runtime/observatory/tests/service/break_on_function_child_isolate_test.dart
index 3922aa6..f1ebfd3 100644
--- a/runtime/observatory/tests/service/break_on_function_child_isolate_test.dart
+++ b/runtime/observatory/tests/service/break_on_function_child_isolate_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--verbose_debug --enable-isolate-groups
+// VMOptions=--verbose_debug
 
 import 'break_on_function_many_child_isolates_test.dart';
 
diff --git a/runtime/observatory/tests/service/break_on_function_many_child_isolates_test.dart b/runtime/observatory/tests/service/break_on_function_many_child_isolates_test.dart
index b0e75a8..0b162ae 100644
--- a/runtime/observatory/tests/service/break_on_function_many_child_isolates_test.dart
+++ b/runtime/observatory/tests/service/break_on_function_many_child_isolates_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--verbose_debug --enable-isolate-groups
+// VMOptions=--verbose_debug
 //
 // Tests breakpoint pausing and resuming with many isolates running and pausing
 // simultaneously.
diff --git a/runtime/observatory/tests/service/object_graph_isolate_group_test.dart b/runtime/observatory/tests/service/object_graph_isolate_group_test.dart
index d325f75..b2580bb 100644
--- a/runtime/observatory/tests/service/object_graph_isolate_group_test.dart
+++ b/runtime/observatory/tests/service/object_graph_isolate_group_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable_isolate_groups
-
 import 'dart:isolate' as isolate;
 import 'package:observatory/object_graph.dart';
 import 'package:observatory/service_io.dart';
diff --git a/runtime/observatory_2/tests/service_2/break_on_function_child_isolate_test.dart b/runtime/observatory_2/tests/service_2/break_on_function_child_isolate_test.dart
index 3922aa6..f1ebfd3 100644
--- a/runtime/observatory_2/tests/service_2/break_on_function_child_isolate_test.dart
+++ b/runtime/observatory_2/tests/service_2/break_on_function_child_isolate_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--verbose_debug --enable-isolate-groups
+// VMOptions=--verbose_debug
 
 import 'break_on_function_many_child_isolates_test.dart';
 
diff --git a/runtime/observatory_2/tests/service_2/break_on_function_many_child_isolates_test.dart b/runtime/observatory_2/tests/service_2/break_on_function_many_child_isolates_test.dart
index e5b6b56..77eb09d 100644
--- a/runtime/observatory_2/tests/service_2/break_on_function_many_child_isolates_test.dart
+++ b/runtime/observatory_2/tests/service_2/break_on_function_many_child_isolates_test.dart
@@ -1,7 +1,7 @@
 // Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
-// VMOptions=--verbose_debug --enable-isolate-groups
+// VMOptions=--verbose_debug
 //
 // Tests breakpoint pausing and resuming with many isolates running and pausing
 // simultaneously.
diff --git a/runtime/observatory_2/tests/service_2/object_graph_isolate_group_test.dart b/runtime/observatory_2/tests/service_2/object_graph_isolate_group_test.dart
index b9ddf82..93bfb77 100644
--- a/runtime/observatory_2/tests/service_2/object_graph_isolate_group_test.dart
+++ b/runtime/observatory_2/tests/service_2/object_graph_isolate_group_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable_isolate_groups
-
 // @dart = 2.7
 
 import 'dart:isolate' as isolate;
diff --git a/runtime/tests/concurrency/run_stress_test_shards.dart b/runtime/tests/concurrency/run_stress_test_shards.dart
index 5f29e01..bae35d6 100644
--- a/runtime/tests/concurrency/run_stress_test_shards.dart
+++ b/runtime/tests/concurrency/run_stress_test_shards.dart
@@ -146,13 +146,11 @@
   JitTestRunner('out/DebugX64', [
     '--disable-dart-dev',
     '--no-sound-null-safety',
-    '--enable-isolate-groups',
     'runtime/tests/concurrency/generated_stress_test.dart.jit.dill',
   ]),
   JitTestRunner('out/ReleaseX64', [
     '--disable-dart-dev',
     '--no-sound-null-safety',
-    '--enable-isolate-groups',
     '--no-inline-alloc',
     '--use-slow-path',
     '--deoptimize-on-runtime-call-every=3',
@@ -165,7 +163,6 @@
       '-Dshard=$i',
       '-Dshards=$tsanShards',
       '--no-sound-null-safety',
-      '--enable-isolate-groups',
       'runtime/tests/concurrency/generated_stress_test.dart.jit.dill',
     ]),
   AotTestRunner('out/ReleaseX64', [
@@ -173,14 +170,12 @@
     'runtime/tests/concurrency/generated_stress_test.dart.aot.dill',
   ], [
     '--no-sound-null-safety',
-    '--enable-isolate-groups',
   ]),
   AotTestRunner('out/DebugX64', [
     '--no-sound-null-safety',
     'runtime/tests/concurrency/generated_stress_test.dart.aot.dill',
   ], [
     '--no-sound-null-safety',
-    '--enable-isolate-groups',
   ]),
 ];
 
diff --git a/runtime/tests/vm/dart/deferred_isolate_test.dart b/runtime/tests/vm/dart/deferred_isolate_test.dart
index 94be755..7afc208 100644
--- a/runtime/tests/vm/dart/deferred_isolate_test.dart
+++ b/runtime/tests/vm/dart/deferred_isolate_test.dart
@@ -4,8 +4,6 @@
 
 // Verify deferred library status is per-isolate, not per-isolate-group.
 
-// VMOptions=--enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 import 'package:expect/expect.dart';
diff --git a/runtime/tests/vm/dart/isolates/closure_entrypoint_test.dart b/runtime/tests/vm/dart/isolates/closure_entrypoint_test.dart
index b855c4f..7b8450e 100644
--- a/runtime/tests/vm/dart/isolates/closure_entrypoint_test.dart
+++ b/runtime/tests/vm/dart/isolates/closure_entrypoint_test.dart
@@ -2,10 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
+// VMOptions=--no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
 
 // The tests in this file will only succeed when isolate groups are enabled
 // (hence the VMOptions above).
diff --git a/runtime/tests/vm/dart/isolates/closures_without_captured_variables_test.dart b/runtime/tests/vm/dart/isolates/closures_without_captured_variables_test.dart
index d7970cc..386d73e 100644
--- a/runtime/tests/vm/dart/isolates/closures_without_captured_variables_test.dart
+++ b/runtime/tests/vm/dart/isolates/closures_without_captured_variables_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-
 // The tests in this file will only succeed when isolate groups are enabled
 // (hence the VMOptions above).
 
diff --git a/runtime/tests/vm/dart/isolates/dart_api_create_lightweight_isolate_test.dart b/runtime/tests/vm/dart/isolates/dart_api_create_lightweight_isolate_test.dart
index f4005be..d4734b8 100644
--- a/runtime/tests/vm/dart/isolates/dart_api_create_lightweight_isolate_test.dart
+++ b/runtime/tests/vm/dart/isolates/dart_api_create_lightweight_isolate_test.dart
@@ -3,8 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 // SharedObjects=ffi_test_functions
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:async';
 import 'dart:ffi';
@@ -17,8 +16,6 @@
 import 'test_utils.dart' show isArtificialReloadMode;
 import '../../../../../tests/ffi/dylib_utils.dart';
 
-final bool isolateGroupsEnabled =
-    Platform.executableArguments.contains('--enable-isolate-groups');
 final bool usesDwarfStackTraces = Platform.executableArguments
     .any((entry) => RegExp('--dwarf[-_]stack[-_]traces').hasMatch(entry));
 final bool hasSymbolicStackTraces = !usesDwarfStackTraces;
@@ -223,25 +220,7 @@
   await testFatalError();
 }
 
-Future testNotSupported() async {
-  dynamic exception;
-  try {
-    FfiBindings.createLightweightIsolate('debug-name', Pointer.fromAddress(0));
-  } catch (e) {
-    exception = e;
-  }
-  Expect.contains(
-      'Lightweight isolates need to be explicitly enabled by passing '
-      '--enable-isolate-groups.',
-      exception.toString());
-}
-
 Future main(args) async {
-  if (!isolateGroupsEnabled) {
-    await testNotSupported();
-    return;
-  }
-
   // This test should not run in hot-reload because of the way it is written
   // (embedder related code written in Dart instead of C)
   if (isArtificialReloadMode) return;
diff --git a/runtime/tests/vm/dart/isolates/fast_object_copy2_test.dart b/runtime/tests/vm/dart/isolates/fast_object_copy2_test.dart
index 3977179..4a2a72f 100644
--- a/runtime/tests/vm/dart/isolates/fast_object_copy2_test.dart
+++ b/runtime/tests/vm/dart/isolates/fast_object_copy2_test.dart
@@ -2,10 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
+// VMOptions=--no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
 
 // The tests in this file will only succeed when isolate groups are enabled
 // (hence the VMOptions above).
diff --git a/runtime/tests/vm/dart/isolates/fast_object_copy_test.dart b/runtime/tests/vm/dart/isolates/fast_object_copy_test.dart
index 169a1b9..955e13d 100644
--- a/runtime/tests/vm/dart/isolates/fast_object_copy_test.dart
+++ b/runtime/tests/vm/dart/isolates/fast_object_copy_test.dart
@@ -2,11 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
+// VMOptions=--no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
+// VMOptions=--enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
 
 // The tests in this file are particularly for an implementation that tries to
 // allocate the entire graph in BFS order using a fast new space allocation
diff --git a/runtime/tests/vm/dart/isolates/fibonacci_call_test.dart b/runtime/tests/vm/dart/isolates/fibonacci_call_test.dart
index daf66e0..04e8684 100644
--- a/runtime/tests/vm/dart/isolates/fibonacci_call_test.dart
+++ b/runtime/tests/vm/dart/isolates/fibonacci_call_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:isolate';
 
diff --git a/runtime/tests/vm/dart/isolates/limited_active_mutator_test.dart b/runtime/tests/vm/dart/isolates/limited_active_mutator_test.dart
index f56e9ee..1fc5a31 100644
--- a/runtime/tests/vm/dart/isolates/limited_active_mutator_test.dart
+++ b/runtime/tests/vm/dart/isolates/limited_active_mutator_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification --disable-thread-pool-limit
+// VMOptions=--disable-heap-verification --disable-thread-pool-limit
 
 import 'dart:async';
 import 'dart:math' as math;
diff --git a/runtime/tests/vm/dart/isolates/regress_46539_test.dart b/runtime/tests/vm/dart/isolates/regress_46539_test.dart
index 0814f0d..148280d 100644
--- a/runtime/tests/vm/dart/isolates/regress_46539_test.dart
+++ b/runtime/tests/vm/dart/isolates/regress_46539_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--optimization-filter=foo --enable-isolate-groups --no-use-osr --optimization-counter-threshold=1 --deterministic
+// VMOptions=--optimization-filter=foo --no-use-osr --optimization-counter-threshold=1 --deterministic
 
 // Important: This is a regression test for a concurrency issue, if this test
 // is flaky it is essentially failing!
diff --git a/runtime/tests/vm/dart/isolates/ring_gc_sendAndExit_test.dart b/runtime/tests/vm/dart/isolates/ring_gc_sendAndExit_test.dart
index a50d9e8..0f9c559 100644
--- a/runtime/tests/vm/dart/isolates/ring_gc_sendAndExit_test.dart
+++ b/runtime/tests/vm/dart/isolates/ring_gc_sendAndExit_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:math' as math;
 
diff --git a/runtime/tests/vm/dart/isolates/ring_gc_test.dart b/runtime/tests/vm/dart/isolates/ring_gc_test.dart
index c27cd6c..ff74f7d 100644
--- a/runtime/tests/vm/dart/isolates/ring_gc_test.dart
+++ b/runtime/tests/vm/dart/isolates/ring_gc_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:async';
 import 'dart:math' as math;
diff --git a/runtime/tests/vm/dart/isolates/spawn_function_test.dart b/runtime/tests/vm/dart/isolates/spawn_function_test.dart
index f2a85ea..d1f4b7b 100644
--- a/runtime/tests/vm/dart/isolates/spawn_function_test.dart
+++ b/runtime/tests/vm/dart/isolates/spawn_function_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import 'dart:async';
 
diff --git a/runtime/tests/vm/dart/isolates/sum_recursive_call_test.dart b/runtime/tests/vm/dart/isolates/sum_recursive_call_test.dart
index 89bcc58..81beb3d 100644
--- a/runtime/tests/vm/dart/isolates/sum_recursive_call_test.dart
+++ b/runtime/tests/vm/dart/isolates/sum_recursive_call_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:isolate';
 
diff --git a/runtime/tests/vm/dart/isolates/sum_recursive_tail_call_test.dart b/runtime/tests/vm/dart/isolates/sum_recursive_tail_call_test.dart
index 866b8f3..9148bcd 100644
--- a/runtime/tests/vm/dart/isolates/sum_recursive_tail_call_test.dart
+++ b/runtime/tests/vm/dart/isolates/sum_recursive_tail_call_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:isolate';
 
diff --git a/runtime/tests/vm/dart/isolates/thread_pool_test.dart b/runtime/tests/vm/dart/isolates/thread_pool_test.dart
index 3d689ca..d12e272 100644
--- a/runtime/tests/vm/dart/isolates/thread_pool_test.dart
+++ b/runtime/tests/vm/dart/isolates/thread_pool_test.dart
@@ -3,7 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 // SharedObjects=ffi_test_functions
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:async';
 import 'dart:ffi';
diff --git a/runtime/tests/vm/dart/issue_31959_31960_test.dart b/runtime/tests/vm/dart/issue_31959_31960_test.dart
index 3ca1be2..6a3a3e5 100644
--- a/runtime/tests/vm/dart/issue_31959_31960_test.dart
+++ b/runtime/tests/vm/dart/issue_31959_31960_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 import 'dart:math';
diff --git a/runtime/tests/vm/dart/regress_46878_test.dart b/runtime/tests/vm/dart/regress_46878_test.dart
index 6ef37bc..ad59a65 100644
--- a/runtime/tests/vm/dart/regress_46878_test.dart
+++ b/runtime/tests/vm/dart/regress_46878_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 
 import 'package:expect/expect.dart';
diff --git a/runtime/tests/vm/dart/regress_47468_test.dart b/runtime/tests/vm/dart/regress_47468_test.dart
deleted file mode 100644
index 1ff1bbe..0000000
--- a/runtime/tests/vm/dart/regress_47468_test.dart
+++ /dev/null
@@ -1,18 +0,0 @@
-// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// Regression test for https://github.com/dart-lang/sdk/issues/47468.
-// Verifies that the sending empty non-const maps works
-
-// VMOptions=--no-enable-isolate-groups
-
-import 'dart:isolate';
-
-void main() async {
-  final nonConstMap = <int, Object>{};
-  final receivePort = ReceivePort();
-  final sendPort = receivePort.sendPort;
-  sendPort.send(nonConstMap);
-  await receivePort.first;
-}
diff --git a/runtime/tests/vm/dart/sendandexit_test.dart b/runtime/tests/vm/dart/sendandexit_test.dart
index a48ec13..90c4e8a 100644
--- a/runtime/tests/vm/dart/sendandexit_test.dart
+++ b/runtime/tests/vm/dart/sendandexit_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
-// VMOptions=--enable-isolate-groups
-//
 // Validates functionality of Isolate.exit().
 
 import 'dart:async';
diff --git a/runtime/tests/vm/dart/spawn_infinite_loop_test.dart b/runtime/tests/vm/dart/spawn_infinite_loop_test.dart
index 3a89e80..cc0fb42 100644
--- a/runtime/tests/vm/dart/spawn_infinite_loop_test.dart
+++ b/runtime/tests/vm/dart/spawn_infinite_loop_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 
 // This test ensures that the VM can kill the spawned isolate during VM
diff --git a/runtime/tests/vm/dart/spawn_shutdown_test.dart b/runtime/tests/vm/dart/spawn_shutdown_test.dart
index d47db32..d1e96925 100644
--- a/runtime/tests/vm/dart/spawn_shutdown_test.dart
+++ b/runtime/tests/vm/dart/spawn_shutdown_test.dart
@@ -2,8 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-asserts --enable-isolate-groups
-// VMOptions=--enable-asserts --no-enable-isolate-groups
+// VMOptions=--enable-asserts
 
 import 'dart:io';
 import 'dart:isolate';
diff --git a/runtime/tests/vm/dart/transferable_test.dart b/runtime/tests/vm/dart/transferable_test.dart
index 2f5155a..9d76575 100644
--- a/runtime/tests/vm/dart/transferable_test.dart
+++ b/runtime/tests/vm/dart/transferable_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test that validates that transferables are faster than regular typed data.
 
 import 'dart:async';
diff --git a/runtime/tests/vm/dart/transferable_throws_test.dart b/runtime/tests/vm/dart/transferable_throws_test.dart
index 201c020..1c3aadf 100644
--- a/runtime/tests/vm/dart/transferable_throws_test.dart
+++ b/runtime/tests/vm/dart/transferable_throws_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test that ensures correct exceptions are thrown when misusing
 // [TransferableTypedData].
 
diff --git a/runtime/tests/vm/dart_2/deferred_isolate_test.dart b/runtime/tests/vm/dart_2/deferred_isolate_test.dart
index ccfcbba..c6283a7 100644
--- a/runtime/tests/vm/dart_2/deferred_isolate_test.dart
+++ b/runtime/tests/vm/dart_2/deferred_isolate_test.dart
@@ -6,9 +6,6 @@
 
 // Verify deferred library status is per-isolate, not per-isolate-group.
 
-// VMOptions=--enable-isolate-groups
-
-import 'dart:async';
 import 'dart:isolate';
 import 'package:expect/expect.dart';
 
diff --git a/runtime/tests/vm/dart_2/isolates/closure_entrypoint_test.dart b/runtime/tests/vm/dart_2/isolates/closure_entrypoint_test.dart
index 4fa05c9..7249cee 100644
--- a/runtime/tests/vm/dart_2/isolates/closure_entrypoint_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/closure_entrypoint_test.dart
@@ -2,10 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
+// VMOptions=--no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
 
 // The tests in this file will only succeed when isolate groups are enabled
 // (hence the VMOptions above).
diff --git a/runtime/tests/vm/dart_2/isolates/closures_without_captured_variables_test.dart b/runtime/tests/vm/dart_2/isolates/closures_without_captured_variables_test.dart
index 3f714b6..ebe5474 100644
--- a/runtime/tests/vm/dart_2/isolates/closures_without_captured_variables_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/closures_without_captured_variables_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-
 // The tests in this file will only succeed when isolate groups are enabled
 // (hence the VMOptions above).
 
diff --git a/runtime/tests/vm/dart_2/isolates/dart_api_create_lightweight_isolate_test.dart b/runtime/tests/vm/dart_2/isolates/dart_api_create_lightweight_isolate_test.dart
index 0a2fd1c..23ffcd0 100644
--- a/runtime/tests/vm/dart_2/isolates/dart_api_create_lightweight_isolate_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/dart_api_create_lightweight_isolate_test.dart
@@ -5,8 +5,7 @@
 // @dart = 2.9
 
 // SharedObjects=ffi_test_functions
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:async';
 import 'dart:ffi';
@@ -19,8 +18,6 @@
 import 'test_utils.dart' show isArtificialReloadMode;
 import '../../../../../tests/ffi/dylib_utils.dart';
 
-final bool isolateGroupsEnabled =
-    Platform.executableArguments.contains('--enable-isolate-groups');
 final bool usesDwarfStackTraces = Platform.executableArguments
     .any((entry) => RegExp('--dwarf[-_]stack[-_]traces').hasMatch(entry));
 final bool hasSymbolicStackTraces = !usesDwarfStackTraces;
@@ -225,25 +222,7 @@
   await testFatalError();
 }
 
-Future testNotSupported() async {
-  dynamic exception;
-  try {
-    FfiBindings.createLightweightIsolate('debug-name', Pointer.fromAddress(0));
-  } catch (e) {
-    exception = e;
-  }
-  Expect.contains(
-      'Lightweight isolates need to be explicitly enabled by passing '
-      '--enable-isolate-groups.',
-      exception.toString());
-}
-
 Future main(args) async {
-  if (!isolateGroupsEnabled) {
-    await testNotSupported();
-    return;
-  }
-
   // This test should not run in hot-reload because of the way it is written
   // (embedder related code written in Dart instead of C)
   if (isArtificialReloadMode) return;
diff --git a/runtime/tests/vm/dart_2/isolates/fast_object_copy2_test.dart b/runtime/tests/vm/dart_2/isolates/fast_object_copy2_test.dart
index 9b8c1f0..99d8e26 100644
--- a/runtime/tests/vm/dart_2/isolates/fast_object_copy2_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/fast_object_copy2_test.dart
@@ -4,10 +4,10 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
+// VMOptions=--no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
+// VMOptions=--enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation
 
 // The tests in this file will only succeed when isolate groups are enabled
 // (hence the VMOptions above).
diff --git a/runtime/tests/vm/dart_2/isolates/fast_object_copy_test.dart b/runtime/tests/vm/dart_2/isolates/fast_object_copy_test.dart
index 1a1512d..09aa46f 100644
--- a/runtime/tests/vm/dart_2/isolates/fast_object_copy_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/fast_object_copy_test.dart
@@ -4,11 +4,10 @@
 
 // @dart = 2.9
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
+// VMOptions=--no-enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
+// VMOptions=--enable-fast-object-copy --gc-on-foc-slow-path --force-evacuation --verify-store-buffer
 
 // The tests in this file are particularly for an implementation that tries to
 // allocate the entire graph in BFS order using a fast new space allocation
diff --git a/runtime/tests/vm/dart_2/isolates/fibonacci_call_test.dart b/runtime/tests/vm/dart_2/isolates/fibonacci_call_test.dart
index 7a097a2..97d9b13 100644
--- a/runtime/tests/vm/dart_2/isolates/fibonacci_call_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/fibonacci_call_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:isolate';
 
diff --git a/runtime/tests/vm/dart_2/isolates/limited_active_mutator_test.dart b/runtime/tests/vm/dart_2/isolates/limited_active_mutator_test.dart
index a99e4ee..b01ac77 100644
--- a/runtime/tests/vm/dart_2/isolates/limited_active_mutator_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/limited_active_mutator_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification --disable-thread-pool-limit
+// VMOptions=--disable-heap-verification --disable-thread-pool-limit
 
 import 'dart:async';
 import 'dart:math' as math;
diff --git a/runtime/tests/vm/dart_2/isolates/regress_46539_test.dart b/runtime/tests/vm/dart_2/isolates/regress_46539_test.dart
index 0f16901..6990bd0 100644
--- a/runtime/tests/vm/dart_2/isolates/regress_46539_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/regress_46539_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--optimization-filter=foo --enable-isolate-groups --no-use-osr --optimization-counter-threshold=1 --deterministic
+// VMOptions=--optimization-filter=foo --no-use-osr --optimization-counter-threshold=1 --deterministic
 
 // Important: This is a regression test for a concurrency issue, if this test
 // is flaky it is essentially failing!
diff --git a/runtime/tests/vm/dart_2/isolates/reload_utils.dart b/runtime/tests/vm/dart_2/isolates/reload_utils.dart
index f9ba12f..c973017 100644
--- a/runtime/tests/vm/dart_2/isolates/reload_utils.dart
+++ b/runtime/tests/vm/dart_2/isolates/reload_utils.dart
@@ -125,7 +125,6 @@
     '--enable-vm-service:0',
     '--disable-dart-dev',
     '--disable-service-auth-codes',
-    '--enable-isolate-groups',
     file
   ];
   final env = Platform.environment;
diff --git a/runtime/tests/vm/dart_2/isolates/ring_gc_sendAndExit_test.dart b/runtime/tests/vm/dart_2/isolates/ring_gc_sendAndExit_test.dart
index 2c7011c..d12ebf6 100644
--- a/runtime/tests/vm/dart_2/isolates/ring_gc_sendAndExit_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/ring_gc_sendAndExit_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:math' as math;
 
diff --git a/runtime/tests/vm/dart_2/isolates/ring_gc_test.dart b/runtime/tests/vm/dart_2/isolates/ring_gc_test.dart
index 908d1a3..46af3c4 100644
--- a/runtime/tests/vm/dart_2/isolates/ring_gc_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/ring_gc_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:async';
 import 'dart:math' as math;
diff --git a/runtime/tests/vm/dart_2/isolates/spawn_function_test.dart b/runtime/tests/vm/dart_2/isolates/spawn_function_test.dart
index 4474a3f..24977d6 100644
--- a/runtime/tests/vm/dart_2/isolates/spawn_function_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/spawn_function_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import 'dart:async';
 
diff --git a/runtime/tests/vm/dart_2/isolates/sum_recursive_call_test.dart b/runtime/tests/vm/dart_2/isolates/sum_recursive_call_test.dart
index 0aba961..39baabc 100644
--- a/runtime/tests/vm/dart_2/isolates/sum_recursive_call_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/sum_recursive_call_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:isolate';
 
diff --git a/runtime/tests/vm/dart_2/isolates/sum_recursive_tail_call_test.dart b/runtime/tests/vm/dart_2/isolates/sum_recursive_tail_call_test.dart
index 85b6f0e..989e1cd 100644
--- a/runtime/tests/vm/dart_2/isolates/sum_recursive_tail_call_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/sum_recursive_tail_call_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:isolate';
 
diff --git a/runtime/tests/vm/dart_2/isolates/thread_pool_test.dart b/runtime/tests/vm/dart_2/isolates/thread_pool_test.dart
index f54a9ce..667bec3 100644
--- a/runtime/tests/vm/dart_2/isolates/thread_pool_test.dart
+++ b/runtime/tests/vm/dart_2/isolates/thread_pool_test.dart
@@ -5,7 +5,7 @@
 // @dart = 2.9
 
 // SharedObjects=ffi_test_functions
-// VMOptions=--enable-isolate-groups --disable-heap-verification
+// VMOptions=--disable-heap-verification
 
 import 'dart:async';
 import 'dart:ffi';
diff --git a/runtime/tests/vm/dart_2/issue_31959_31960_test.dart b/runtime/tests/vm/dart_2/issue_31959_31960_test.dart
index 9f79c7c..cc2d8e6 100644
--- a/runtime/tests/vm/dart_2/issue_31959_31960_test.dart
+++ b/runtime/tests/vm/dart_2/issue_31959_31960_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 import 'dart:math';
diff --git a/runtime/tests/vm/dart_2/regress_46878_test.dart b/runtime/tests/vm/dart_2/regress_46878_test.dart
index 6ef37bc..ad59a65 100644
--- a/runtime/tests/vm/dart_2/regress_46878_test.dart
+++ b/runtime/tests/vm/dart_2/regress_46878_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 
 import 'package:expect/expect.dart';
diff --git a/runtime/tests/vm/dart_2/regress_47468_test.dart b/runtime/tests/vm/dart_2/regress_47468_test.dart
deleted file mode 100644
index b1ccb10..0000000
--- a/runtime/tests/vm/dart_2/regress_47468_test.dart
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright (c) 2021, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// Regression test for https://github.com/dart-lang/sdk/issues/47468.
-// Verifies that the sending empty non-const maps works
-
-// VMOptions=--no-enable-isolate-groups
-
-// @dart = 2.9
-
-import 'dart:isolate';
-
-void main() async {
-  final nonConstMap = <int, Object>{};
-  final receivePort = ReceivePort();
-  final sendPort = receivePort.sendPort;
-  sendPort.send(nonConstMap);
-  await receivePort.first;
-}
diff --git a/runtime/tests/vm/dart_2/sendandexit_test.dart b/runtime/tests/vm/dart_2/sendandexit_test.dart
index bf2ffe2..f64ac6a 100644
--- a/runtime/tests/vm/dart_2/sendandexit_test.dart
+++ b/runtime/tests/vm/dart_2/sendandexit_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 //
-// VMOptions=--enable-isolate-groups
-//
 // Validates functionality of Isolate.exit().
 
 // @dart = 2.9
diff --git a/runtime/tests/vm/dart_2/spawn_infinite_loop_test.dart b/runtime/tests/vm/dart_2/spawn_infinite_loop_test.dart
index c87cf77..1d66659 100644
--- a/runtime/tests/vm/dart_2/spawn_infinite_loop_test.dart
+++ b/runtime/tests/vm/dart_2/spawn_infinite_loop_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 
 // This test ensures that the VM can kill the spawned isolate during VM
diff --git a/runtime/tests/vm/dart_2/spawn_shutdown_test.dart b/runtime/tests/vm/dart_2/spawn_shutdown_test.dart
index 4c4eb86..5b30f4f 100644
--- a/runtime/tests/vm/dart_2/spawn_shutdown_test.dart
+++ b/runtime/tests/vm/dart_2/spawn_shutdown_test.dart
@@ -2,8 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-asserts --enable-isolate-groups
-// VMOptions=--enable-asserts --no-enable-isolate-groups
+// VMOptions=--enable-asserts
 
 // @dart = 2.9
 
diff --git a/runtime/tests/vm/dart_2/transferable_test.dart b/runtime/tests/vm/dart_2/transferable_test.dart
index e08040e..1a38483 100644
--- a/runtime/tests/vm/dart_2/transferable_test.dart
+++ b/runtime/tests/vm/dart_2/transferable_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test that validates that transferables are faster than regular typed data.
 
 import 'dart:async';
diff --git a/runtime/tests/vm/dart_2/transferable_throws_test.dart b/runtime/tests/vm/dart_2/transferable_throws_test.dart
index 320ec01..d985cbc 100644
--- a/runtime/tests/vm/dart_2/transferable_throws_test.dart
+++ b/runtime/tests/vm/dart_2/transferable_throws_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test that ensures correct exceptions are thrown when misusing
 // [TransferableTypedData].
 
diff --git a/tests/ffi/snapshot_test.dart b/tests/ffi/snapshot_test.dart
index b27b88b..29a870d 100644
--- a/tests/ffi/snapshot_test.dart
+++ b/tests/ffi/snapshot_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Checks that the VM throws an appropriate exception when FFI objects are
 // passed between isolates.
 
diff --git a/tests/ffi/vmspecific_function_callbacks_test.dart b/tests/ffi/vmspecific_function_callbacks_test.dart
index 6d192a9..0e70e23 100644
--- a/tests/ffi/vmspecific_function_callbacks_test.dart
+++ b/tests/ffi/vmspecific_function_callbacks_test.dart
@@ -5,8 +5,6 @@
 //
 // Dart test program for testing dart:ffi function pointers with callbacks.
 //
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // VMOptions=--stacktrace-every=100
 // VMOptions=--write-protect-code --no-dual-map-code
 // VMOptions=--write-protect-code --no-dual-map-code --stacktrace-every=100
diff --git a/tests/ffi_2/snapshot_test.dart b/tests/ffi_2/snapshot_test.dart
index 7574cea..0452b5b 100644
--- a/tests/ffi_2/snapshot_test.dart
+++ b/tests/ffi_2/snapshot_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Checks that the VM throws an appropriate exception when FFI objects are
 // passed between isolates.
 
diff --git a/tests/ffi_2/vmspecific_function_callbacks_test.dart b/tests/ffi_2/vmspecific_function_callbacks_test.dart
index e86bb95..63bcc67 100644
--- a/tests/ffi_2/vmspecific_function_callbacks_test.dart
+++ b/tests/ffi_2/vmspecific_function_callbacks_test.dart
@@ -7,8 +7,6 @@
 // Dart test program for testing dart:ffi function pointers with callbacks.
 //
 // SharedObjects=ffi_test_functions
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // VMOptions=--stacktrace-every=100
 // VMOptions=--use-slow-path
 // VMOptions=--use-slow-path --stacktrace-every=100
diff --git a/tests/language/regress/regress23244_test.dart b/tests/language/regress/regress23244_test.dart
index 6a25b57..24a1d9b 100644
--- a/tests/language/regress/regress23244_test.dart
+++ b/tests/language/regress/regress23244_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test case for http://dartbug.com/23244
 import 'dart:async';
 import 'dart:isolate';
diff --git a/tests/language/vm/optimized_guarded_field_isolates_test.dart b/tests/language/vm/optimized_guarded_field_isolates_test.dart
index 9278ea9..facc699 100644
--- a/tests/language/vm/optimized_guarded_field_isolates_test.dart
+++ b/tests/language/vm/optimized_guarded_field_isolates_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // VMOptions=--optimization_counter_threshold=100 --no-background_compilation
 
 // Test field type tracking and field list-length tracking in the presence of
diff --git a/tests/language/vm/regress_flutter_89584_test.dart b/tests/language/vm/regress_flutter_89584_test.dart
index 7fa3a2e..2dd0e3e 100644
--- a/tests/language/vm/regress_flutter_89584_test.dart
+++ b/tests/language/vm/regress_flutter_89584_test.dart
@@ -6,9 +6,6 @@
 // https://github.com/flutter/flutter/issues/89584.
 // Verifies a Field::RecordStore is not done before all fields populated.
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups
-
 import 'dart:isolate';
 import 'dart:typed_data';
 
diff --git a/tests/language_2/regress/regress23244_test.dart b/tests/language_2/regress/regress23244_test.dart
index 1fb8a80..e3669e7 100644
--- a/tests/language_2/regress/regress23244_test.dart
+++ b/tests/language_2/regress/regress23244_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test case for http://dartbug.com/23244
 import 'dart:async';
 import 'dart:isolate';
diff --git a/tests/language_2/vm/optimized_guarded_field_isolates_test.dart b/tests/language_2/vm/optimized_guarded_field_isolates_test.dart
index be65d88..6a505bb 100644
--- a/tests/language_2/vm/optimized_guarded_field_isolates_test.dart
+++ b/tests/language_2/vm/optimized_guarded_field_isolates_test.dart
@@ -4,8 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // VMOptions=--optimization_counter_threshold=100 --no-background_compilation
 
 // Test field type tracking and field list-length tracking in the presence of
diff --git a/tests/language_2/vm/regress_flutter_89584_test.dart b/tests/language_2/vm/regress_flutter_89584_test.dart
index be08ce9..1fa00e7 100644
--- a/tests/language_2/vm/regress_flutter_89584_test.dart
+++ b/tests/language_2/vm/regress_flutter_89584_test.dart
@@ -8,9 +8,6 @@
 // https://github.com/flutter/flutter/issues/89584.
 // Verifies a Field::RecordStore is not done before all fields populated.
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups
-
 import 'dart:isolate';
 import 'dart:typed_data';
 
diff --git a/tests/lib/isolate/bool_from_environment_default_value_test.dart b/tests/lib/isolate/bool_from_environment_default_value_test.dart
index fb9d49b..42975ed 100644
--- a/tests/lib/isolate/bool_from_environment_default_value_test.dart
+++ b/tests/lib/isolate/bool_from_environment_default_value_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/capability_test.dart b/tests/lib/isolate/capability_test.dart
index fd6c4d3..589c5c6 100644
--- a/tests/lib/isolate/capability_test.dart
+++ b/tests/lib/isolate/capability_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib/isolate/compile_time_error_test.dart b/tests/lib/isolate/compile_time_error_test.dart
index 21197fa..3eeb36f 100644
--- a/tests/lib/isolate/compile_time_error_test.dart
+++ b/tests/lib/isolate/compile_time_error_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that errors thrown from isolates are
 // processed correctly and don't result in crashes.
 
@@ -16,9 +13,9 @@
 
 class TestClass {
   TestClass.named(num this.fld1)
-  // Should cause a compilation error (for the spawned isolate). It is a
-  // runtime error for the test.
-    : fld2 = this.fld1 // //# 01: compile-time error
+      // Should cause a compilation error (for the spawned isolate). It is a
+      // runtime error for the test.
+      : fld2 = this.fld1 // //# 01: compile-time error
   ;
   late num fld1;
   late num fld2;
diff --git a/tests/lib/isolate/count_test.dart b/tests/lib/isolate/count_test.dart
index cc96b3f..8c82091 100644
--- a/tests/lib/isolate/count_test.dart
+++ b/tests/lib/isolate/count_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 library CountTest;
 
diff --git a/tests/lib/isolate/cross_isolate_message_test.dart b/tests/lib/isolate/cross_isolate_message_test.dart
index ede3792..b9ba881 100644
--- a/tests/lib/isolate/cross_isolate_message_test.dart
+++ b/tests/lib/isolate/cross_isolate_message_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates can communicate to isolates
 // other than the main isolate.
 
diff --git a/tests/lib/isolate/deferred_in_isolate2_test.dart b/tests/lib/isolate/deferred_in_isolate2_test.dart
index 52e5428..e63ce8f 100644
--- a/tests/lib/isolate/deferred_in_isolate2_test.dart
+++ b/tests/lib/isolate/deferred_in_isolate2_test.dart
@@ -2,13 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library deferred_in_isolate2_test;
 
 import 'dart:isolate';
-import 'dart:async';
 import 'package:async_helper/async_minitest.dart';
 
 import 'deferred_in_isolate2_lib.dart' deferred as lib;
diff --git a/tests/lib/isolate/deferred_in_isolate_test.dart b/tests/lib/isolate/deferred_in_isolate_test.dart
index d44f075..496b064 100644
--- a/tests/lib/isolate/deferred_in_isolate_test.dart
+++ b/tests/lib/isolate/deferred_in_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test that deferred libraries are supported from isolates other than the root
 // isolate.
 
diff --git a/tests/lib/isolate/enum_const_test.dart b/tests/lib/isolate/enum_const_test.dart
index 0a57f13..292ba89 100644
--- a/tests/lib/isolate/enum_const_test.dart
+++ b/tests/lib/isolate/enum_const_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib/isolate/error_at_spawn_test.dart b/tests/lib/isolate/error_at_spawn_test.dart
index c22f41e..4f5b373 100644
--- a/tests/lib/isolate/error_at_spawn_test.dart
+++ b/tests/lib/isolate/error_at_spawn_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/error_at_spawnuri_test.dart b/tests/lib/isolate/error_at_spawnuri_test.dart
index 6d0e073..f74c881 100644
--- a/tests/lib/isolate/error_at_spawnuri_test.dart
+++ b/tests/lib/isolate/error_at_spawnuri_test.dart
@@ -2,13 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_at_spawnuri;
 
 import "dart:isolate";
-import "dart:async";
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib/isolate/error_exit_at_spawn_test.dart b/tests/lib/isolate/error_exit_at_spawn_test.dart
index 9543025..603bcb6 100644
--- a/tests/lib/isolate/error_exit_at_spawn_test.dart
+++ b/tests/lib/isolate/error_exit_at_spawn_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_exit_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/error_exit_at_spawnuri_test.dart b/tests/lib/isolate/error_exit_at_spawnuri_test.dart
index cf32b98..6e9a5a8 100644
--- a/tests/lib/isolate/error_exit_at_spawnuri_test.dart
+++ b/tests/lib/isolate/error_exit_at_spawnuri_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_exit_at_spawnuri;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/exit_at_spawn_test.dart b/tests/lib/isolate/exit_at_spawn_test.dart
index 4a2574e..119ca7e 100644
--- a/tests/lib/isolate/exit_at_spawn_test.dart
+++ b/tests/lib/isolate/exit_at_spawn_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library exit_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/exit_at_spawnuri_test.dart b/tests/lib/isolate/exit_at_spawnuri_test.dart
index 5bb9ed8..f415c66 100644
--- a/tests/lib/isolate/exit_at_spawnuri_test.dart
+++ b/tests/lib/isolate/exit_at_spawnuri_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library exit_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/fast_copy_during_initial_message_test.dart b/tests/lib/isolate/fast_copy_during_initial_message_test.dart
index 375de09..4741fd7 100644
--- a/tests/lib/isolate/fast_copy_during_initial_message_test.dart
+++ b/tests/lib/isolate/fast_copy_during_initial_message_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:isolate";
 
diff --git a/tests/lib/isolate/function_send1_test.dart b/tests/lib/isolate/function_send1_test.dart
index 1955c96..5743aa1 100644
--- a/tests/lib/isolate/function_send1_test.dart
+++ b/tests/lib/isolate/function_send1_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/function_send_test.dart b/tests/lib/isolate/function_send_test.dart
index cd5ee40..ad90779 100644
--- a/tests/lib/isolate/function_send_test.dart
+++ b/tests/lib/isolate/function_send_test.dart
@@ -2,20 +2,15 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:isolate";
-import "dart:io";
 import "dart:async";
 
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 
-final bool isolateGroupsEnabled =
-    Platform.executableArguments.contains('--enable-isolate-groups');
-
 void toplevel(port, message) {
   port.send("toplevel:$message");
 }
@@ -65,38 +60,17 @@
   // Sendables are top-level functions and static functions only.
   testSendable("toplevel", toplevel);
   testSendable("static", C.staticFunc);
-  // Unsendables are any closure - instance methods or function expression.
-  var c = new C();
-  testUnsendable("instance method", c.instanceMethod);
-  testUnsendable("static context expression", createFuncToplevel());
-  testUnsendable("static context expression", C.createFuncStatic());
-  testUnsendable("initializer context expression", c.initializer);
-  testUnsendable("constructor context expression", c.body);
-  testUnsendable("instance method context expression", c.createFuncMember());
 
   // The result of `toplevel.call` and `staticFunc.call` may or may not be
   // identical to `toplevel` and `staticFunc` respectively. If they are not
   // equal, they may or may not be considered toplevel/static functions anyway,
   // and therefore sendable. The VM and dart2js currently disagree on whether
   // `toplevel` and `toplevel.call` are identical, both allow them to be sent.
-  // If this is ever specified to something else, use:
-  //     testUnsendable("toplevel.call", toplevel.call);
-  //     testUnsendable("static.call", C.staticFunc.call);
-  // instead.
   // These two tests should be considered canaries for accidental behavior
   // change rather than requirements.
   testSendable("toplevel", toplevel.call);
   testSendable("static", C.staticFunc.call);
 
-  // Callable objects are sendable if general objects are (VM yes, dart2js no).
-  // It's unspecified whether arbitrary objects can be sent. If it is specified,
-  // add a test that `new Callable()` is either sendable or unsendable.
-
-  // The call method of a callable object is a closure holding the object,
-  // not a top-level or static function, so it should be blocked, just as
-  // a normal method.
-  testUnsendable("callable object", new Callable().call);
-
   asyncEnd();
   return;
 }
@@ -179,51 +153,6 @@
   initPort.send(singleMessagePort(callFunc));
 }
 
-void testUnsendable(name, func) {
-  // Isolate group support does allow sending closures.
-  if (isolateGroupsEnabled) return;
-
-  asyncStart();
-  Isolate.spawn(nop, func).then<void>((v) => throw "allowed spawn direct?",
-      onError: (e, s) {
-    asyncEnd();
-  });
-  asyncStart();
-  Isolate.spawn(nop, [func]).then<void>((v) => throw "allowed spawn wrapped?",
-      onError: (e, s) {
-    asyncEnd();
-  });
-
-  asyncStart();
-  var noReply = new RawReceivePort((_) {
-    throw "Unexpected message: $_";
-  });
-  Expect.throws(() {
-    noReply.sendPort.send(func);
-  }, (_) => true, "send direct");
-  Expect.throws(() {
-    noReply.sendPort.send([func]);
-  }, (_) => true, "send wrapped");
-  scheduleMicrotask(() {
-    noReply.close();
-    asyncEnd();
-  });
-
-  // Try sending through other isolate.
-  asyncStart();
-  echoPort((v) {
-    Expect.equals(0, v);
-  }).then((p) {
-    try {
-      p.send(func);
-    } finally {
-      p.send(0); //   Closes echo port.
-    }
-  }).then<void>((p) => throw "unreachable 2", onError: (e, s) {
-    asyncEnd();
-  });
-}
-
 void nop(_) {}
 
 void callFunc(message) {
diff --git a/tests/lib/isolate/handle_error2_test.dart b/tests/lib/isolate/handle_error2_test.dart
index 8e36364..22d86f9 100644
--- a/tests/lib/isolate/handle_error2_test.dart
+++ b/tests/lib/isolate/handle_error2_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library handle_error_test;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/handle_error3_test.dart b/tests/lib/isolate/handle_error3_test.dart
index 170f130..743b1c8 100644
--- a/tests/lib/isolate/handle_error3_test.dart
+++ b/tests/lib/isolate/handle_error3_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library handle_error_test;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/handle_error_test.dart b/tests/lib/isolate/handle_error_test.dart
index a453072..c2298b3 100644
--- a/tests/lib/isolate/handle_error_test.dart
+++ b/tests/lib/isolate/handle_error_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library handle_error_test;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/illegal_msg_function_test.dart b/tests/lib/isolate/illegal_msg_function_test.dart
deleted file mode 100644
index 62cbe70..0000000
--- a/tests/lib/isolate/illegal_msg_function_test.dart
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// VMOptions=--no-enable-isolate-groups
-
-library illegal_msg_function_test;
-
-import "dart:isolate";
-
-import "package:expect/expect.dart";
-import "package:async_helper/async_helper.dart";
-
-echo(sendPort) {
-  var port = new ReceivePort();
-  sendPort.send(port.sendPort);
-  port.listen((msg) {
-    sendPort.send("echoing ${msg(1)}}");
-  });
-}
-
-void main() {
-  asyncStart();
-
-  final port = new ReceivePort();
-
-  // Ignore returned Future.
-  Isolate.spawn(echo, port.sendPort);
-
-  port.first.then((_snd) {
-    SendPort snd = _snd;
-    int function(x) => x + 2;
-    try {
-      snd.send(function);
-    } catch (e) {
-      // Expected behavior.
-      port.close();
-      asyncEnd();
-      return;
-    }
-    Expect.fail("Should not be reached. Message sending didn't throw.");
-  });
-}
diff --git a/tests/lib/isolate/illegal_msg_mirror_test.dart b/tests/lib/isolate/illegal_msg_mirror_test.dart
index a15572d..fdc4ffb 100644
--- a/tests/lib/isolate/illegal_msg_mirror_test.dart
+++ b/tests/lib/isolate/illegal_msg_mirror_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library illegal_msg_mirror_test;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/int32_length_overflow_test.dart b/tests/lib/isolate/int32_length_overflow_test.dart
index 85e2bd7..3502ce9 100644
--- a/tests/lib/isolate/int32_length_overflow_test.dart
+++ b/tests/lib/isolate/int32_length_overflow_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:isolate";
 import "dart:typed_data";
diff --git a/tests/lib/isolate/int_from_environment_default_value_test.dart b/tests/lib/isolate/int_from_environment_default_value_test.dart
index af7ccac..cb598ee 100644
--- a/tests/lib/isolate/int_from_environment_default_value_test.dart
+++ b/tests/lib/isolate/int_from_environment_default_value_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib/isolate/isolate_complex_messages_test.dart b/tests/lib/isolate/isolate_complex_messages_test.dart
index bbf728d..74a3a1a 100644
--- a/tests/lib/isolate/isolate_complex_messages_test.dart
+++ b/tests/lib/isolate/isolate_complex_messages_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Dart test program for testing isolate communication with
 // complex messages.
diff --git a/tests/lib/isolate/isolate_current_test.dart b/tests/lib/isolate/isolate_current_test.dart
index 1c2f1bb..3701fdd 100644
--- a/tests/lib/isolate/isolate_current_test.dart
+++ b/tests/lib/isolate/isolate_current_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 library isolate_current_test;
 
diff --git a/tests/lib/isolate/isolate_import_test.dart b/tests/lib/isolate/isolate_import_test.dart
index 781e13c..d286c89 100644
--- a/tests/lib/isolate/isolate_import_test.dart
+++ b/tests/lib/isolate/isolate_import_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library IsolateImportNegativeTest;
 
 // Omitting the following import is an error:
diff --git a/tests/lib/isolate/issue_21398_parent_isolate1_test.dart b/tests/lib/isolate/issue_21398_parent_isolate1_test.dart
index 6a0b458..1b15b8b 100644
--- a/tests/lib/isolate/issue_21398_parent_isolate1_test.dart
+++ b/tests/lib/isolate/issue_21398_parent_isolate1_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import "package:expect/expect.dart";
 import 'package:async_helper/async_helper.dart';
diff --git a/tests/lib/isolate/issue_21398_parent_isolate2_test.dart b/tests/lib/isolate/issue_21398_parent_isolate2_test.dart
index feee51b..0fe1043 100644
--- a/tests/lib/isolate/issue_21398_parent_isolate2_test.dart
+++ b/tests/lib/isolate/issue_21398_parent_isolate2_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import "package:expect/expect.dart";
 import 'package:async_helper/async_helper.dart';
diff --git a/tests/lib/isolate/issue_21398_parent_isolate_test.dart b/tests/lib/isolate/issue_21398_parent_isolate_test.dart
index 5264827..891ccf8 100644
--- a/tests/lib/isolate/issue_21398_parent_isolate_test.dart
+++ b/tests/lib/isolate/issue_21398_parent_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import "package:expect/expect.dart";
 import 'package:async_helper/async_helper.dart';
diff --git a/tests/lib/isolate/issue_22778_test.dart b/tests/lib/isolate/issue_22778_test.dart
index 28107cc..51f5a19 100644
--- a/tests/lib/isolate/issue_22778_test.dart
+++ b/tests/lib/isolate/issue_22778_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib/isolate/issue_24243_parent_isolate_test.dart b/tests/lib/isolate/issue_24243_parent_isolate_test.dart
index c38e5e4..84b2201 100644
--- a/tests/lib/isolate/issue_24243_parent_isolate_test.dart
+++ b/tests/lib/isolate/issue_24243_parent_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:collection';
 import 'dart:isolate';
 
diff --git a/tests/lib/isolate/issue_35626_test.dart b/tests/lib/isolate/issue_35626_test.dart
index 2b392ad..e943c54 100644
--- a/tests/lib/isolate/issue_35626_test.dart
+++ b/tests/lib/isolate/issue_35626_test.dart
@@ -2,16 +2,14 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Tests that sets of enums can be set through ports.
 // https://github.com/dart-lang/sdk/issues/35626
 
 library spawn_tests;
 
-import "dart:io";
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib/isolate/issue_6610_test.dart b/tests/lib/isolate/issue_6610_test.dart
index 962955e..96cc5e8f 100644
--- a/tests/lib/isolate/issue_6610_test.dart
+++ b/tests/lib/isolate/issue_6610_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Testing that Isolate.spawn copies the source code of the parent isolate,
 // rather than rereading the parent's source URI.
 // https://github.com/dart-lang/sdk/issues/6610
diff --git a/tests/lib/isolate/kill2_test.dart b/tests/lib/isolate/kill2_test.dart
index 9391fc8..53e5c10 100644
--- a/tests/lib/isolate/kill2_test.dart
+++ b/tests/lib/isolate/kill2_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/kill_infinite_loop_in_initializer_test.dart b/tests/lib/isolate/kill_infinite_loop_in_initializer_test.dart
index 1d41541..41f4dce 100644
--- a/tests/lib/isolate/kill_infinite_loop_in_initializer_test.dart
+++ b/tests/lib/isolate/kill_infinite_loop_in_initializer_test.dart
@@ -2,15 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test against out-of-band messages being blocked during lazy
 // static field initialization.
 
 import "dart:isolate";
-import "dart:async";
-import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 
 dynamic staticFieldWithBadInitializer = badInitializer();
diff --git a/tests/lib/isolate/kill_self_synchronously_test.dart b/tests/lib/isolate/kill_self_synchronously_test.dart
index 19f3a2e..b405d30 100644
--- a/tests/lib/isolate/kill_self_synchronously_test.dart
+++ b/tests/lib/isolate/kill_self_synchronously_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:io";
 
diff --git a/tests/lib/isolate/kill_self_test.dart b/tests/lib/isolate/kill_self_test.dart
index 157b30f..c482439 100644
--- a/tests/lib/isolate/kill_self_test.dart
+++ b/tests/lib/isolate/kill_self_test.dart
@@ -2,12 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
-import "package:expect/expect.dart";
+
 import "package:async_helper/async_helper.dart";
 
 isomain1(replyPort) {
diff --git a/tests/lib/isolate/kill_test.dart b/tests/lib/isolate/kill_test.dart
index 07e0dfe8..5b65c04 100644
--- a/tests/lib/isolate/kill_test.dart
+++ b/tests/lib/isolate/kill_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/large_byte_data_leak_test.dart b/tests/lib/isolate/large_byte_data_leak_test.dart
index 9797a54..ee19255 100644
--- a/tests/lib/isolate/large_byte_data_leak_test.dart
+++ b/tests/lib/isolate/large_byte_data_leak_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:async";
 import "dart:developer" show UserTag;
diff --git a/tests/lib/isolate/large_byte_data_test.dart b/tests/lib/isolate/large_byte_data_test.dart
index 8a78238..d9e3d24 100644
--- a/tests/lib/isolate/large_byte_data_test.dart
+++ b/tests/lib/isolate/large_byte_data_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:isolate";
 import "dart:typed_data";
diff --git a/tests/lib/isolate/mandel_isolate_test.dart b/tests/lib/isolate/mandel_isolate_test.dart
index 50d564a..9aa5d5e 100644
--- a/tests/lib/isolate/mandel_isolate_test.dart
+++ b/tests/lib/isolate/mandel_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library MandelIsolateTest;
 
 import 'dart:async';
diff --git a/tests/lib/isolate/message2_test.dart b/tests/lib/isolate/message2_test.dart
index fd7550c..1c15990 100644
--- a/tests/lib/isolate/message2_test.dart
+++ b/tests/lib/isolate/message2_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Dart test program for testing serialization of messages.
 // VMOptions=--enable_type_checks --enable_asserts
diff --git a/tests/lib/isolate/message3_test.dart b/tests/lib/isolate/message3_test.dart
index 6809c95..a40ece1 100644
--- a/tests/lib/isolate/message3_test.dart
+++ b/tests/lib/isolate/message3_test.dart
@@ -2,13 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Dart test program for testing serialization of messages.
-// VMOptions=--enable_type_checks --enable_asserts --enable-isolate-groups
-// VMOptions=--enable_type_checks --enable_asserts --no-enable-isolate-groups
+// VMOptions=--enable_type_checks --enable_asserts
 
 library MessageTest;
 
@@ -21,9 +19,6 @@
 import 'package:expect/expect.dart';
 import 'dart:typed_data';
 
-final bool isolateGroupsEnabled =
-    Platform.executableArguments.contains('--enable-isolate-groups');
-
 void echoMain(msg) {
   SendPort replyTo = msg[0];
   SendPort pong = msg[1];
@@ -414,14 +409,10 @@
     Expect.equals(42, x.fun()); //     //# fun: continued
   }); //                               //# fun: continued
 
-  if (isolateGroupsEnabled) {
-    ping.send(new E(new E(E.fooFun).instanceFun));
-    checks.add((x) {
-      Expect.equals(1234, (x as E).fun());
-    });
-  } else {
-    Expect.throws(() => ping.send(new E(new E(E.fooFun).instanceFun)));
-  }
+  ping.send(new E(new E(E.fooFun).instanceFun));
+  checks.add((x) {
+    Expect.equals(1234, (x as E).fun());
+  });
 
   F nonConstF = new F();
   ping.send(nonConstF);
diff --git a/tests/lib/isolate/message4_test.dart b/tests/lib/isolate/message4_test.dart
index 4644ddb..b593770 100644
--- a/tests/lib/isolate/message4_test.dart
+++ b/tests/lib/isolate/message4_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing serialization of messages with static
 // native functions.
 
diff --git a/tests/lib/isolate/message_const_type_arguments_1_test.dart b/tests/lib/isolate/message_const_type_arguments_1_test.dart
index e5133aa..b31c5e7 100644
--- a/tests/lib/isolate/message_const_type_arguments_1_test.dart
+++ b/tests/lib/isolate/message_const_type_arguments_1_test.dart
@@ -2,14 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // https://github.com/dart-lang/sdk/issues/35778
 
 import "dart:async";
 import "dart:isolate";
-import "dart:typed_data";
+
 import "package:expect/expect.dart";
 
 void child(replyPort) {
diff --git a/tests/lib/isolate/message_const_type_arguments_2_test.dart b/tests/lib/isolate/message_const_type_arguments_2_test.dart
index 002aa6e..382cbeb 100644
--- a/tests/lib/isolate/message_const_type_arguments_2_test.dart
+++ b/tests/lib/isolate/message_const_type_arguments_2_test.dart
@@ -2,14 +2,11 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // https://github.com/dart-lang/sdk/issues/35778
 
 import "dart:async";
 import "dart:isolate";
-import "dart:typed_data";
+
 import "package:expect/expect.dart";
 
 void child(replyPort) {
diff --git a/tests/lib/isolate/message_enum_test.dart b/tests/lib/isolate/message_enum_test.dart
index 801afd4d..6f5a145 100644
--- a/tests/lib/isolate/message_enum_test.dart
+++ b/tests/lib/isolate/message_enum_test.dart
@@ -2,12 +2,10 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
+import "dart:isolate";
 
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
-import "dart:isolate";
 
 enum Foo { BAR, BAZ }
 
diff --git a/tests/lib/isolate/message_test.dart b/tests/lib/isolate/message_test.dart
index 8a7ec69..0f5ba46 100644
--- a/tests/lib/isolate/message_test.dart
+++ b/tests/lib/isolate/message_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing serialization of messages.
 // VMOptions=--enable_type_checks --enable_asserts
 
diff --git a/tests/lib/isolate/mint_maker_test.dart b/tests/lib/isolate/mint_maker_test.dart
index c4b25ec..59eb9b0 100644
--- a/tests/lib/isolate/mint_maker_test.dart
+++ b/tests/lib/isolate/mint_maker_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library MintMakerTest;
 
 import 'dart:async';
diff --git a/tests/lib/isolate/native_wrapper_message_test.dart b/tests/lib/isolate/native_wrapper_message_test.dart
index 366a84b..bc9ed01 100644
--- a/tests/lib/isolate/native_wrapper_message_test.dart
+++ b/tests/lib/isolate/native_wrapper_message_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import 'dart:nativewrappers';
 import 'package:expect/expect.dart';
diff --git a/tests/lib/isolate/nested_spawn2_test.dart b/tests/lib/isolate/nested_spawn2_test.dart
index d335909..c4a4f57 100644
--- a/tests/lib/isolate/nested_spawn2_test.dart
+++ b/tests/lib/isolate/nested_spawn2_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates can spawn other isolates and
 // that the nested isolates can communicate with the main once the spawner has
 // disappeared.
diff --git a/tests/lib/isolate/nested_spawn_test.dart b/tests/lib/isolate/nested_spawn_test.dart
index 0bc8c77..0074c5f 100644
--- a/tests/lib/isolate/nested_spawn_test.dart
+++ b/tests/lib/isolate/nested_spawn_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates can spawn other isolates.
 
 library NestedSpawnTest;
diff --git a/tests/lib/isolate/non_fatal_exception_in_timer_callback_test.dart b/tests/lib/isolate/non_fatal_exception_in_timer_callback_test.dart
index b361171..4568afe 100644
--- a/tests/lib/isolate/non_fatal_exception_in_timer_callback_test.dart
+++ b/tests/lib/isolate/non_fatal_exception_in_timer_callback_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 import 'dart:io';
diff --git a/tests/lib/isolate/object_leak_test.dart b/tests/lib/isolate/object_leak_test.dart
index b8b94b4..4fd195d 100644
--- a/tests/lib/isolate/object_leak_test.dart
+++ b/tests/lib/isolate/object_leak_test.dart
@@ -2,17 +2,14 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test for http://dartbug.com/18942
 
 library LeakTest;
 
+import 'dart:isolate';
+
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
-import 'dart:isolate';
-import 'dart:async';
 
 class A {
   var x = 0;
diff --git a/tests/lib/isolate/ondone_test.dart b/tests/lib/isolate/ondone_test.dart
index f378855..ddcb49e 100644
--- a/tests/lib/isolate/ondone_test.dart
+++ b/tests/lib/isolate/ondone_test.dart
@@ -2,11 +2,9 @@
 // for details. All rights reserved. Use of this source is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
+
 import "package:async_helper/async_helper.dart";
 
 void isomain(SendPort replyPort) {
diff --git a/tests/lib/isolate/package_config_test.dart b/tests/lib/isolate/package_config_test.dart
index a2cfece..faffc35 100644
--- a/tests/lib/isolate/package_config_test.dart
+++ b/tests/lib/isolate/package_config_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // VMOptions=--trace_shutdown
+
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib/isolate/package_resolve_test.dart b/tests/lib/isolate/package_resolve_test.dart
index 50686a3..3199de7 100644
--- a/tests/lib/isolate/package_resolve_test.dart
+++ b/tests/lib/isolate/package_resolve_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib/isolate/package_root_test.dart b/tests/lib/isolate/package_root_test.dart
index 390df69..7d6e7b6 100644
--- a/tests/lib/isolate/package_root_test.dart
+++ b/tests/lib/isolate/package_root_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib/isolate/pause_test.dart b/tests/lib/isolate/pause_test.dart
index 1e97f00a..f8c64ec 100644
--- a/tests/lib/isolate/pause_test.dart
+++ b/tests/lib/isolate/pause_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib/isolate/ping_pause_test.dart b/tests/lib/isolate/ping_pause_test.dart
index 48ad135..c29e594 100644
--- a/tests/lib/isolate/ping_pause_test.dart
+++ b/tests/lib/isolate/ping_pause_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/ping_test.dart b/tests/lib/isolate/ping_test.dart
index 4371a4c0..fe92a57 100644
--- a/tests/lib/isolate/ping_test.dart
+++ b/tests/lib/isolate/ping_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/port_test.dart b/tests/lib/isolate/port_test.dart
index 937d75e..a0ec0f5 100644
--- a/tests/lib/isolate/port_test.dart
+++ b/tests/lib/isolate/port_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test properties of ports.
 
 library PortTest;
diff --git a/tests/lib/isolate/raw_port_test.dart b/tests/lib/isolate/raw_port_test.dart
index 6f24212..51ccdc0 100644
--- a/tests/lib/isolate/raw_port_test.dart
+++ b/tests/lib/isolate/raw_port_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test RawReceivePort.
 
 library raw_port_test;
diff --git a/tests/lib/isolate/regress_34752_test.dart b/tests/lib/isolate/regress_34752_test.dart
index ed870a6..e96cf8d 100644
--- a/tests/lib/isolate/regress_34752_test.dart
+++ b/tests/lib/isolate/regress_34752_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Verifies that large BigInt can be passed through a message port and
 // simple arithmetic operations still work after that.
diff --git a/tests/lib/isolate/regress_flutter_22796_test.dart b/tests/lib/isolate/regress_flutter_22796_test.dart
index 1cab5f1..1e6fc13 100644
--- a/tests/lib/isolate/regress_flutter_22796_test.dart
+++ b/tests/lib/isolate/regress_flutter_22796_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Verifies that large typed data can be passed in a field through message port.
 // This is a regression test for
 // https://github.com/flutter/flutter/issues/22796.
diff --git a/tests/lib/isolate/request_reply_test.dart b/tests/lib/isolate/request_reply_test.dart
index 54d4d7c..4d910b4 100644
--- a/tests/lib/isolate/request_reply_test.dart
+++ b/tests/lib/isolate/request_reply_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library RequestReplyTest;
 
 import 'dart:isolate';
diff --git a/tests/lib/isolate/resolve_package_uri_test.dart b/tests/lib/isolate/resolve_package_uri_test.dart
index 9ea1d03..00d9ddb 100644
--- a/tests/lib/isolate/resolve_package_uri_test.dart
+++ b/tests/lib/isolate/resolve_package_uri_test.dart
@@ -2,13 +2,9 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test for faulty encoding of `Isolate.resolvePackageUri` by
 // dart2js.
 
-import 'dart:async';
 import 'dart:isolate';
 
 main() {
diff --git a/tests/lib/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart b/tests/lib/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart
index 50686a3..3199de7 100644
--- a/tests/lib/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart
+++ b/tests/lib/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib/isolate/send_private_test.dart b/tests/lib/isolate/send_private_test.dart
index 8ed717f..57df312 100644
--- a/tests/lib/isolate/send_private_test.dart
+++ b/tests/lib/isolate/send_private_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib/isolate/simple_message_test.dart b/tests/lib/isolate/simple_message_test.dart
index f0310af..2ca65cb 100644
--- a/tests/lib/isolate/simple_message_test.dart
+++ b/tests/lib/isolate/simple_message_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates are spawned.
 
 library IsolateNegativeTest;
diff --git a/tests/lib/isolate/spawn_function_custom_class_test.dart b/tests/lib/isolate/spawn_function_custom_class_test.dart
index 0046cef..0fa9156 100644
--- a/tests/lib/isolate/spawn_function_custom_class_test.dart
+++ b/tests/lib/isolate/spawn_function_custom_class_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Create a user-defined class in a new isolate.
 //
 // Regression test for vm bug 2235: We were forgetting to finalize
diff --git a/tests/lib/isolate/spawn_function_test.dart b/tests/lib/isolate/spawn_function_test.dart
index bd8d1c1..3f1d3c0 100644
--- a/tests/lib/isolate/spawn_function_test.dart
+++ b/tests/lib/isolate/spawn_function_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of spawning an isolate from a function.
 library spawn_tests;
 
diff --git a/tests/lib/isolate/spawn_generic_test.dart b/tests/lib/isolate/spawn_generic_test.dart
index 109f2a8..3f5f88f 100644
--- a/tests/lib/isolate/spawn_generic_test.dart
+++ b/tests/lib/isolate/spawn_generic_test.dart
@@ -2,16 +2,13 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Check that Isolate.spawn is generic.
 library spawn_generic;
 
 import "dart:isolate";
 import "dart:async";
+
 import "package:async_helper/async_helper.dart";
-import "package:expect/expect.dart";
 
 void isomain(num args) {
   print(args);
diff --git a/tests/lib/isolate/spawn_uri_exported_main_test.dart b/tests/lib/isolate/spawn_uri_exported_main_test.dart
index 837486e..1c3efe6 100644
--- a/tests/lib/isolate/spawn_uri_exported_main_test.dart
+++ b/tests/lib/isolate/spawn_uri_exported_main_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:isolate";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/spawn_uri_fail_test.dart b/tests/lib/isolate/spawn_uri_fail_test.dart
index 6c9dc98..8d46548 100644
--- a/tests/lib/isolate/spawn_uri_fail_test.dart
+++ b/tests/lib/isolate/spawn_uri_fail_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:io";
 import "dart:isolate";
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/spawn_uri_missing_from_isolate_test.dart b/tests/lib/isolate/spawn_uri_missing_from_isolate_test.dart
index 02521b6..445edc1 100644
--- a/tests/lib/isolate/spawn_uri_missing_from_isolate_test.dart
+++ b/tests/lib/isolate/spawn_uri_missing_from_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 /// Tests that Isolate.spawnUri completes with an error when the given URI
 /// doesn't resolve to an existing resource.
 ///
diff --git a/tests/lib/isolate/spawn_uri_missing_test.dart b/tests/lib/isolate/spawn_uri_missing_test.dart
index 19344ba..42f2c78 100644
--- a/tests/lib/isolate/spawn_uri_missing_test.dart
+++ b/tests/lib/isolate/spawn_uri_missing_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 /// Tests that Isolate.spanUri completes with an error when the given URI
 /// doesn't resolve to an existing resource.
 library test.isolate.spawn_uri_missing_test;
diff --git a/tests/lib/isolate/spawn_uri_multi_test.dart b/tests/lib/isolate/spawn_uri_multi_test.dart
index d5fdc46..2984fca 100644
--- a/tests/lib/isolate/spawn_uri_multi_test.dart
+++ b/tests/lib/isolate/spawn_uri_multi_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Negative test to make sure that we are reaching all assertions.
 library spawn_tests;
 
diff --git a/tests/lib/isolate/spawn_uri_nested_vm_test.dart b/tests/lib/isolate/spawn_uri_nested_vm_test.dart
index 0847cf6..8a1b6d5 100644
--- a/tests/lib/isolate/spawn_uri_nested_vm_test.dart
+++ b/tests/lib/isolate/spawn_uri_nested_vm_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of nested spawning of isolates from a URI
 library NestedSpawnUriLibrary;
 
diff --git a/tests/lib/isolate/spawn_uri_test.dart b/tests/lib/isolate/spawn_uri_test.dart
index 28d7bce..2df4a52 100644
--- a/tests/lib/isolate/spawn_uri_test.dart
+++ b/tests/lib/isolate/spawn_uri_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of spawning an isolate from a URI
 library spawn_tests;
 
diff --git a/tests/lib/isolate/spawn_uri_vm_test.dart b/tests/lib/isolate/spawn_uri_vm_test.dart
index 3832b42..a3b8f61 100644
--- a/tests/lib/isolate/spawn_uri_vm_test.dart
+++ b/tests/lib/isolate/spawn_uri_vm_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of spawning an isolate from a URI
 library spawn_tests;
 
diff --git a/tests/lib/isolate/start_paused_test.dart b/tests/lib/isolate/start_paused_test.dart
index c9b2b57..e7a0b84 100644
--- a/tests/lib/isolate/start_paused_test.dart
+++ b/tests/lib/isolate/start_paused_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library start_paused_test;
 
 import "dart:isolate";
diff --git a/tests/lib/isolate/static_function_test.dart b/tests/lib/isolate/static_function_test.dart
index 0708dc3..aa60edd 100644
--- a/tests/lib/isolate/static_function_test.dart
+++ b/tests/lib/isolate/static_function_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test starting isolate with static functions (and toplevel ones, for sanity).
 
 library static_function_test;
@@ -116,9 +113,6 @@
 }
 
 void main([args, port]) {
-  final bool isolateGroupsEnabled =
-      Platform.executableArguments.contains('--enable-isolate-groups');
-
   asyncStart();
   // Sanity check.
   spawnTest("function", function, "TOP");
@@ -138,31 +132,17 @@
   spawnTest("lib._class._function", lib.privateClassFunction, "_LIB");
   spawnTest("lib._class._function", lib.privateClassAndFunction, "_LIBPRIVATE");
 
-  if (isolateGroupsEnabled) {
-    spawnTest("static closure", staticClosure, "WHAT?");
-    spawnTest("dynamic closure", dynamicClosure, "WHAT??");
-    spawnTest("named dynamic closure", namedDynamicClosure, "WHAT FOO??");
-    spawnTest("instance closure", new C().instanceClosure, "C WHAT?");
-    spawnTest(
-        "initializer closure", new C().constructorInitializerClosure, "Init?");
-    spawnTest(
-        "constructor closure", new C().constructorBodyClosure, "bodyClosure?");
-    spawnTest("named constructor closure", new C().namedConstructorBodyClosure,
-        "namedBodyClosure?");
-    spawnTest("instance method", new C().instanceMethod, "INSTANCE WHAT?");
-  } else {
-    // Negative tests
-    functionFailTest("static closure", staticClosure);
-    functionFailTest("dynamic closure", dynamicClosure);
-    functionFailTest("named dynamic closure", namedDynamicClosure);
-    functionFailTest("instance closure", new C().instanceClosure);
-    functionFailTest(
-        "initializer closure", new C().constructorInitializerClosure);
-    functionFailTest("constructor closure", new C().constructorBodyClosure);
-    functionFailTest(
-        "named constructor closure", new C().namedConstructorBodyClosure);
-    functionFailTest("instance method", new C().instanceMethod);
-  }
+  spawnTest("static closure", staticClosure, "WHAT?");
+  spawnTest("dynamic closure", dynamicClosure, "WHAT??");
+  spawnTest("named dynamic closure", namedDynamicClosure, "WHAT FOO??");
+  spawnTest("instance closure", new C().instanceClosure, "C WHAT?");
+  spawnTest(
+      "initializer closure", new C().constructorInitializerClosure, "Init?");
+  spawnTest(
+      "constructor closure", new C().constructorBodyClosure, "bodyClosure?");
+  spawnTest("named constructor closure", new C().namedConstructorBodyClosure,
+      "namedBodyClosure?");
+  spawnTest("instance method", new C().instanceMethod, "INSTANCE WHAT?");
 
   asyncEnd();
 }
diff --git a/tests/lib/isolate/string_from_environment_default_value_test.dart b/tests/lib/isolate/string_from_environment_default_value_test.dart
index 78b2feb..165e044 100644
--- a/tests/lib/isolate/string_from_environment_default_value_test.dart
+++ b/tests/lib/isolate/string_from_environment_default_value_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:expect/expect.dart";
diff --git a/tests/lib/isolate/timer_isolate_test.dart b/tests/lib/isolate/timer_isolate_test.dart
index 58e93c5..a34005a 100644
--- a/tests/lib/isolate/timer_isolate_test.dart
+++ b/tests/lib/isolate/timer_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library multiple_timer_test;
 
 import 'dart:isolate';
diff --git a/tests/lib/isolate/timer_multiple_isolates_test.dart b/tests/lib/isolate/timer_multiple_isolates_test.dart
index 3f7d8f3..0e47a88 100644
--- a/tests/lib/isolate/timer_multiple_isolates_test.dart
+++ b/tests/lib/isolate/timer_multiple_isolates_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library timer_multiple_isolates_test;
 
 import 'dart:isolate';
diff --git a/tests/lib/isolate/transferable_failed_to_send_test.dart b/tests/lib/isolate/transferable_failed_to_send_test.dart
index c1d714a..f399576 100644
--- a/tests/lib/isolate/transferable_failed_to_send_test.dart
+++ b/tests/lib/isolate/transferable_failed_to_send_test.dart
@@ -2,16 +2,14 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:io" show ServerSocket;
 import "dart:isolate";
 import "dart:typed_data" show ByteData;
 
 import "package:expect/expect.dart";
-import "package:async_helper/async_helper.dart";
 
 void main() async {
   final port = new ReceivePort();
diff --git a/tests/lib/isolate/transferable_test.dart b/tests/lib/isolate/transferable_test.dart
index 2264c8c..419c2b6 100644
--- a/tests/lib/isolate/transferable_test.dart
+++ b/tests/lib/isolate/transferable_test.dart
@@ -2,9 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:async";
 import "dart:collection";
diff --git a/tests/lib/isolate/typed_message_test.dart b/tests/lib/isolate/typed_message_test.dart
index 38e24d0..a0327ea 100644
--- a/tests/lib/isolate/typed_message_test.dart
+++ b/tests/lib/isolate/typed_message_test.dart
@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // Dart test program for testing isolate communication with
 // typed objects.
 
diff --git a/tests/lib/isolate/unresolved_ports_test.dart b/tests/lib/isolate/unresolved_ports_test.dart
index 7707fab..9ac7995 100644
--- a/tests/lib/isolate/unresolved_ports_test.dart
+++ b/tests/lib/isolate/unresolved_ports_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // spawns multiple isolates and sends unresolved ports between them.
 library unresolved_ports;
 
diff --git a/tests/lib/isolate/vm_rehash_test.dart b/tests/lib/isolate/vm_rehash_test.dart
index f5a0a73..7b1b6c4 100644
--- a/tests/lib/isolate/vm_rehash_test.dart
+++ b/tests/lib/isolate/vm_rehash_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 
diff --git a/tests/lib/isolate/weak_property_message_1_test.dart b/tests/lib/isolate/weak_property_message_1_test.dart
index 4946222..b475bd3 100644
--- a/tests/lib/isolate/weak_property_message_1_test.dart
+++ b/tests/lib/isolate/weak_property_message_1_test.dart
@@ -4,9 +4,6 @@
 
 // See https://github.com/dart-lang/sdk/issues/25559
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib/isolate/weak_property_message_2_test.dart b/tests/lib/isolate/weak_property_message_2_test.dart
index fd0dbc6..0b572e7 100644
--- a/tests/lib/isolate/weak_property_message_2_test.dart
+++ b/tests/lib/isolate/weak_property_message_2_test.dart
@@ -4,9 +4,6 @@
 
 // See https://github.com/dart-lang/sdk/issues/25559
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups
-
 import "dart:developer";
 import "dart:isolate";
 
diff --git a/tests/lib_2/isolate/bool_from_environment_default_value_test.dart b/tests/lib_2/isolate/bool_from_environment_default_value_test.dart
index fe0bd39..aaa2feb 100644
--- a/tests/lib_2/isolate/bool_from_environment_default_value_test.dart
+++ b/tests/lib_2/isolate/bool_from_environment_default_value_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/capability_test.dart b/tests/lib_2/isolate/capability_test.dart
index 5f4ef37..a6570c5 100644
--- a/tests/lib_2/isolate/capability_test.dart
+++ b/tests/lib_2/isolate/capability_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib_2/isolate/compile_time_error_test.dart b/tests/lib_2/isolate/compile_time_error_test.dart
index da85090..88a37d7 100644
--- a/tests/lib_2/isolate/compile_time_error_test.dart
+++ b/tests/lib_2/isolate/compile_time_error_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that errors thrown from isolates are
 // processed correctly and don't result in crashes.
 
@@ -18,9 +15,9 @@
 
 class TestClass {
   TestClass.named(num this.fld1)
-  // Should cause a compilation error (for the spawned isolate). It is a
-  // runtime error for the test.
-    : fld2 = this.fld1 // //# 01: compile-time error
+      // Should cause a compilation error (for the spawned isolate). It is a
+      // runtime error for the test.
+      : fld2 = this.fld1 // //# 01: compile-time error
   ;
   num fld1;
   num fld2;
diff --git a/tests/lib_2/isolate/count_test.dart b/tests/lib_2/isolate/count_test.dart
index e351ef9..90d3d4e 100644
--- a/tests/lib_2/isolate/count_test.dart
+++ b/tests/lib_2/isolate/count_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 library CountTest;
 
diff --git a/tests/lib_2/isolate/cross_isolate_message_test.dart b/tests/lib_2/isolate/cross_isolate_message_test.dart
index 59b9ed6..7d23e24 100644
--- a/tests/lib_2/isolate/cross_isolate_message_test.dart
+++ b/tests/lib_2/isolate/cross_isolate_message_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates can communicate to isolates
 // other than the main isolate.
 
diff --git a/tests/lib_2/isolate/deferred_in_isolate2_test.dart b/tests/lib_2/isolate/deferred_in_isolate2_test.dart
index 0db87c3..7f1cb88 100644
--- a/tests/lib_2/isolate/deferred_in_isolate2_test.dart
+++ b/tests/lib_2/isolate/deferred_in_isolate2_test.dart
@@ -4,13 +4,9 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library deferred_in_isolate2_test;
 
 import 'dart:isolate';
-import 'dart:async';
 import 'package:async_helper/async_minitest.dart';
 
 import 'deferred_in_isolate2_lib.dart' deferred as lib;
diff --git a/tests/lib_2/isolate/deferred_in_isolate_test.dart b/tests/lib_2/isolate/deferred_in_isolate_test.dart
index 25d9fcf4..42ae7e2 100644
--- a/tests/lib_2/isolate/deferred_in_isolate_test.dart
+++ b/tests/lib_2/isolate/deferred_in_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test that deferred libraries are supported from isolates other than the root
 // isolate.
 
diff --git a/tests/lib_2/isolate/enum_const_test.dart b/tests/lib_2/isolate/enum_const_test.dart
index b93202d..09e3d2d 100644
--- a/tests/lib_2/isolate/enum_const_test.dart
+++ b/tests/lib_2/isolate/enum_const_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib_2/isolate/error_at_spawn_test.dart b/tests/lib_2/isolate/error_at_spawn_test.dart
index 7eab826..0847d2f 100644
--- a/tests/lib_2/isolate/error_at_spawn_test.dart
+++ b/tests/lib_2/isolate/error_at_spawn_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/error_at_spawnuri_test.dart b/tests/lib_2/isolate/error_at_spawnuri_test.dart
index 8d7254d..0329798 100644
--- a/tests/lib_2/isolate/error_at_spawnuri_test.dart
+++ b/tests/lib_2/isolate/error_at_spawnuri_test.dart
@@ -4,13 +4,9 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_at_spawnuri;
 
 import "dart:isolate";
-import "dart:async";
 import "package:async_helper/async_helper.dart";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib_2/isolate/error_exit_at_spawn_test.dart b/tests/lib_2/isolate/error_exit_at_spawn_test.dart
index 17f5cd6..83f29d1 100644
--- a/tests/lib_2/isolate/error_exit_at_spawn_test.dart
+++ b/tests/lib_2/isolate/error_exit_at_spawn_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_exit_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/error_exit_at_spawnuri_test.dart b/tests/lib_2/isolate/error_exit_at_spawnuri_test.dart
index 8b43578..b4b5831 100644
--- a/tests/lib_2/isolate/error_exit_at_spawnuri_test.dart
+++ b/tests/lib_2/isolate/error_exit_at_spawnuri_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library error_exit_at_spawnuri;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/exit_at_spawn_test.dart b/tests/lib_2/isolate/exit_at_spawn_test.dart
index ca8cfa5..203ea66 100644
--- a/tests/lib_2/isolate/exit_at_spawn_test.dart
+++ b/tests/lib_2/isolate/exit_at_spawn_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library exit_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/exit_at_spawnuri_test.dart b/tests/lib_2/isolate/exit_at_spawnuri_test.dart
index f6f4919..cc4000a 100644
--- a/tests/lib_2/isolate/exit_at_spawnuri_test.dart
+++ b/tests/lib_2/isolate/exit_at_spawnuri_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library exit_at_spawn;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/fast_copy_during_initial_message_test.dart b/tests/lib_2/isolate/fast_copy_during_initial_message_test.dart
index 15c3978..8111991 100644
--- a/tests/lib_2/isolate/fast_copy_during_initial_message_test.dart
+++ b/tests/lib_2/isolate/fast_copy_during_initial_message_test.dart
@@ -4,7 +4,7 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:isolate";
 
diff --git a/tests/lib_2/isolate/function_send1_test.dart b/tests/lib_2/isolate/function_send1_test.dart
index 2acd91b..c4defba 100644
--- a/tests/lib_2/isolate/function_send1_test.dart
+++ b/tests/lib_2/isolate/function_send1_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/function_send_test.dart b/tests/lib_2/isolate/function_send_test.dart
index 1f208e7..d3ac5fd 100644
--- a/tests/lib_2/isolate/function_send_test.dart
+++ b/tests/lib_2/isolate/function_send_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:isolate";
 import "dart:io";
@@ -15,9 +14,6 @@
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 
-final bool isolateGroupsEnabled =
-    Platform.executableArguments.contains('--enable-isolate-groups');
-
 void toplevel(port, message) {
   port.send("toplevel:$message");
 }
@@ -68,38 +64,17 @@
   // Sendables are top-level functions and static functions only.
   testSendable("toplevel", toplevel);
   testSendable("static", C.staticFunc);
-  // Unsendables are any closure - instance methods or function expression.
-  var c = new C();
-  testUnsendable("instance method", c.instanceMethod);
-  testUnsendable("static context expression", createFuncToplevel());
-  testUnsendable("static context expression", C.createFuncStatic());
-  testUnsendable("initializer context expression", c.initializer);
-  testUnsendable("constructor context expression", c.body);
-  testUnsendable("instance method context expression", c.createFuncMember());
 
   // The result of `toplevel.call` and `staticFunc.call` may or may not be
   // identical to `toplevel` and `staticFunc` respectively. If they are not
   // equal, they may or may not be considered toplevel/static functions anyway,
   // and therefore sendable. The VM and dart2js currently disagree on whether
   // `toplevel` and `toplevel.call` are identical, both allow them to be sent.
-  // If this is ever specified to something else, use:
-  //     testUnsendable("toplevel.call", toplevel.call);
-  //     testUnsendable("static.call", C.staticFunc.call);
-  // instead.
   // These two tests should be considered canaries for accidental behavior
   // change rather than requirements.
   testSendable("toplevel", toplevel.call);
   testSendable("static", C.staticFunc.call);
 
-  // Callable objects are sendable if general objects are (VM yes, dart2js no).
-  // It's unspecified whether arbitrary objects can be sent. If it is specified,
-  // add a test that `new Callable()` is either sendable or unsendable.
-
-  // The call method of a callable object is a closure holding the object,
-  // not a top-level or static function, so it should be blocked, just as
-  // a normal method.
-  testUnsendable("callable object", new Callable().call);
-
   asyncEnd();
   return;
 }
@@ -182,51 +157,6 @@
   initPort.send(singleMessagePort(callFunc));
 }
 
-void testUnsendable(name, func) {
-  // Isolate group support does allow sending closures.
-  if (isolateGroupsEnabled) return;
-
-  asyncStart();
-  Isolate.spawn(nop, func).then((v) => throw "allowed spawn direct?",
-      onError: (e, s) {
-    asyncEnd();
-  });
-  asyncStart();
-  Isolate.spawn(nop, [func]).then((v) => throw "allowed spawn wrapped?",
-      onError: (e, s) {
-    asyncEnd();
-  });
-
-  asyncStart();
-  var noReply = new RawReceivePort((_) {
-    throw "Unexpected message: $_";
-  });
-  Expect.throws(() {
-    noReply.sendPort.send(func);
-  }, null, "send direct");
-  Expect.throws(() {
-    noReply.sendPort.send([func]);
-  }, null, "send wrapped");
-  scheduleMicrotask(() {
-    noReply.close();
-    asyncEnd();
-  });
-
-  // Try sending through other isolate.
-  asyncStart();
-  echoPort((v) {
-    Expect.equals(0, v);
-  }).then((p) {
-    try {
-      p.send(func);
-    } finally {
-      p.send(0); //   Closes echo port.
-    }
-  }).then((p) => throw "unreachable 2", onError: (e, s) {
-    asyncEnd();
-  });
-}
-
 void nop(_) {}
 
 void callFunc(message) {
diff --git a/tests/lib_2/isolate/handle_error2_test.dart b/tests/lib_2/isolate/handle_error2_test.dart
index 0a09262..33fa371 100644
--- a/tests/lib_2/isolate/handle_error2_test.dart
+++ b/tests/lib_2/isolate/handle_error2_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library handle_error_test;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/handle_error3_test.dart b/tests/lib_2/isolate/handle_error3_test.dart
index 4d4db96..f6d3c9b7 100644
--- a/tests/lib_2/isolate/handle_error3_test.dart
+++ b/tests/lib_2/isolate/handle_error3_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library handle_error_test;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/handle_error_test.dart b/tests/lib_2/isolate/handle_error_test.dart
index cbc707f..c095862 100644
--- a/tests/lib_2/isolate/handle_error_test.dart
+++ b/tests/lib_2/isolate/handle_error_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library handle_error_test;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/illegal_msg_function_test.dart b/tests/lib_2/isolate/illegal_msg_function_test.dart
deleted file mode 100644
index dbd3699..0000000
--- a/tests/lib_2/isolate/illegal_msg_function_test.dart
+++ /dev/null
@@ -1,45 +0,0 @@
-// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// @dart = 2.9
-
-// VMOptions=--no-enable-isolate-groups
-
-library illegal_msg_function_test;
-
-import "dart:isolate";
-
-import "package:expect/expect.dart";
-import "package:async_helper/async_helper.dart";
-
-echo(sendPort) {
-  var port = new ReceivePort();
-  sendPort.send(port.sendPort);
-  port.listen((msg) {
-    sendPort.send("echoing ${msg(1)}}");
-  });
-}
-
-void main() {
-  asyncStart();
-
-  final port = new ReceivePort();
-
-  // Ignore returned Future.
-  Isolate.spawn(echo, port.sendPort);
-
-  port.first.then((_snd) {
-    SendPort snd = _snd;
-    int function(x) => x + 2;
-    try {
-      snd.send(function);
-    } catch (e) {
-      // Expected behavior.
-      port.close();
-      asyncEnd();
-      return;
-    }
-    Expect.fail("Should not be reached. Message sending didn't throw.");
-  });
-}
diff --git a/tests/lib_2/isolate/illegal_msg_mirror_test.dart b/tests/lib_2/isolate/illegal_msg_mirror_test.dart
index ada58e9..0e4fa15 100644
--- a/tests/lib_2/isolate/illegal_msg_mirror_test.dart
+++ b/tests/lib_2/isolate/illegal_msg_mirror_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library illegal_msg_mirror_test;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/int32_length_overflow_test.dart b/tests/lib_2/isolate/int32_length_overflow_test.dart
index 9d97252..bccdb54 100644
--- a/tests/lib_2/isolate/int32_length_overflow_test.dart
+++ b/tests/lib_2/isolate/int32_length_overflow_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:isolate";
 import "dart:typed_data";
diff --git a/tests/lib_2/isolate/int_from_environment_default_value_test.dart b/tests/lib_2/isolate/int_from_environment_default_value_test.dart
index fdf1c67..f30c852 100644
--- a/tests/lib_2/isolate/int_from_environment_default_value_test.dart
+++ b/tests/lib_2/isolate/int_from_environment_default_value_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib_2/isolate/isolate_complex_messages_test.dart b/tests/lib_2/isolate/isolate_complex_messages_test.dart
index 6599829..e044aae 100644
--- a/tests/lib_2/isolate/isolate_complex_messages_test.dart
+++ b/tests/lib_2/isolate/isolate_complex_messages_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Dart test program for testing isolate communication with
 // complex messages.
diff --git a/tests/lib_2/isolate/isolate_current_test.dart b/tests/lib_2/isolate/isolate_current_test.dart
index c5d1432..99b2efe 100644
--- a/tests/lib_2/isolate/isolate_current_test.dart
+++ b/tests/lib_2/isolate/isolate_current_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 library isolate_current_test;
 
diff --git a/tests/lib_2/isolate/isolate_import_test.dart b/tests/lib_2/isolate/isolate_import_test.dart
index 02f5276..9a2a569 100644
--- a/tests/lib_2/isolate/isolate_import_test.dart
+++ b/tests/lib_2/isolate/isolate_import_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library IsolateImportNegativeTest;
 
 // Omitting the following import is an error:
diff --git a/tests/lib_2/isolate/issue_21398_parent_isolate1_test.dart b/tests/lib_2/isolate/issue_21398_parent_isolate1_test.dart
index 314d563..3188cdd 100644
--- a/tests/lib_2/isolate/issue_21398_parent_isolate1_test.dart
+++ b/tests/lib_2/isolate/issue_21398_parent_isolate1_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import "package:expect/expect.dart";
 import 'package:async_helper/async_helper.dart';
diff --git a/tests/lib_2/isolate/issue_21398_parent_isolate2_test.dart b/tests/lib_2/isolate/issue_21398_parent_isolate2_test.dart
index a22fcb5..62e802d 100644
--- a/tests/lib_2/isolate/issue_21398_parent_isolate2_test.dart
+++ b/tests/lib_2/isolate/issue_21398_parent_isolate2_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import "package:expect/expect.dart";
 import 'package:async_helper/async_helper.dart';
diff --git a/tests/lib_2/isolate/issue_21398_parent_isolate_test.dart b/tests/lib_2/isolate/issue_21398_parent_isolate_test.dart
index 86f28b4..6772cd0 100644
--- a/tests/lib_2/isolate/issue_21398_parent_isolate_test.dart
+++ b/tests/lib_2/isolate/issue_21398_parent_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import "package:expect/expect.dart";
 import 'package:async_helper/async_helper.dart';
diff --git a/tests/lib_2/isolate/issue_22778_test.dart b/tests/lib_2/isolate/issue_22778_test.dart
index 6675134..a21fdf3 100644
--- a/tests/lib_2/isolate/issue_22778_test.dart
+++ b/tests/lib_2/isolate/issue_22778_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib_2/isolate/issue_24243_parent_isolate_test.dart b/tests/lib_2/isolate/issue_24243_parent_isolate_test.dart
index 7def95e..d292e8b 100644
--- a/tests/lib_2/isolate/issue_24243_parent_isolate_test.dart
+++ b/tests/lib_2/isolate/issue_24243_parent_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:collection';
 import 'dart:isolate';
 
diff --git a/tests/lib_2/isolate/issue_35626_test.dart b/tests/lib_2/isolate/issue_35626_test.dart
index 83c371c..57a6cb3 100644
--- a/tests/lib_2/isolate/issue_35626_test.dart
+++ b/tests/lib_2/isolate/issue_35626_test.dart
@@ -4,16 +4,14 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Tests that sets of enums can be set through ports.
 // https://github.com/dart-lang/sdk/issues/35626
 
 library spawn_tests;
 
-import "dart:io";
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib_2/isolate/kill2_test.dart b/tests/lib_2/isolate/kill2_test.dart
index e363a3d..0ee1d62 100644
--- a/tests/lib_2/isolate/kill2_test.dart
+++ b/tests/lib_2/isolate/kill2_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/kill_infinite_loop_in_initializer_test.dart b/tests/lib_2/isolate/kill_infinite_loop_in_initializer_test.dart
index 591b187..5b5a92b 100644
--- a/tests/lib_2/isolate/kill_infinite_loop_in_initializer_test.dart
+++ b/tests/lib_2/isolate/kill_infinite_loop_in_initializer_test.dart
@@ -4,15 +4,10 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test against out-of-band messages being blocked during lazy
 // static field initialization.
 
 import "dart:isolate";
-import "dart:async";
-import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 
 dynamic staticFieldWithBadInitializer = badInitializer();
diff --git a/tests/lib_2/isolate/kill_self_synchronously_test.dart b/tests/lib_2/isolate/kill_self_synchronously_test.dart
index 74edac1..d8eb448 100644
--- a/tests/lib_2/isolate/kill_self_synchronously_test.dart
+++ b/tests/lib_2/isolate/kill_self_synchronously_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:io";
 
diff --git a/tests/lib_2/isolate/kill_self_test.dart b/tests/lib_2/isolate/kill_self_test.dart
index 0ea47b5..8f01f26 100644
--- a/tests/lib_2/isolate/kill_self_test.dart
+++ b/tests/lib_2/isolate/kill_self_test.dart
@@ -4,12 +4,9 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
-import "package:expect/expect.dart";
+
 import "package:async_helper/async_helper.dart";
 
 isomain1(replyPort) {
diff --git a/tests/lib_2/isolate/kill_test.dart b/tests/lib_2/isolate/kill_test.dart
index dd53477..4966bba 100644
--- a/tests/lib_2/isolate/kill_test.dart
+++ b/tests/lib_2/isolate/kill_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/large_byte_data_leak_test.dart b/tests/lib_2/isolate/large_byte_data_leak_test.dart
index 76fafd5..fda98f7 100644
--- a/tests/lib_2/isolate/large_byte_data_leak_test.dart
+++ b/tests/lib_2/isolate/large_byte_data_leak_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:async";
 import "dart:developer" show UserTag;
diff --git a/tests/lib_2/isolate/large_byte_data_test.dart b/tests/lib_2/isolate/large_byte_data_test.dart
index ff55e0a..be1ce00 100644
--- a/tests/lib_2/isolate/large_byte_data_test.dart
+++ b/tests/lib_2/isolate/large_byte_data_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:isolate";
 import "dart:typed_data";
diff --git a/tests/lib_2/isolate/mandel_isolate_test.dart b/tests/lib_2/isolate/mandel_isolate_test.dart
index 1d75cb2..249b366 100644
--- a/tests/lib_2/isolate/mandel_isolate_test.dart
+++ b/tests/lib_2/isolate/mandel_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library MandelIsolateTest;
 
 import 'dart:async';
diff --git a/tests/lib_2/isolate/message2_test.dart b/tests/lib_2/isolate/message2_test.dart
index 81892d4..76ac027 100644
--- a/tests/lib_2/isolate/message2_test.dart
+++ b/tests/lib_2/isolate/message2_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Dart test program for testing serialization of messages.
 // VMOptions=--enable_type_checks --enable_asserts
diff --git a/tests/lib_2/isolate/message3_test.dart b/tests/lib_2/isolate/message3_test.dart
index 4eb2c6b..37ddee5 100644
--- a/tests/lib_2/isolate/message3_test.dart
+++ b/tests/lib_2/isolate/message3_test.dart
@@ -4,13 +4,11 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Dart test program for testing serialization of messages.
-// VMOptions=--enable_type_checks --enable_asserts --enable-isolate-groups
-// VMOptions=--enable_type_checks --enable_asserts --no-enable-isolate-groups
+// VMOptions=--enable_type_checks --enable_asserts
 
 library MessageTest;
 
@@ -23,9 +21,6 @@
 import 'package:expect/expect.dart';
 import 'dart:typed_data';
 
-final bool isolateGroupsEnabled =
-    Platform.executableArguments.contains('--enable-isolate-groups');
-
 void echoMain(msg) {
   SendPort replyTo = msg[0];
   SendPort pong = msg[1];
@@ -416,14 +411,10 @@
     Expect.equals(42, x.fun()); //     //# fun: continued
   }); //                               //# fun: continued
 
-  if (isolateGroupsEnabled) {
-    ping.send(new E(new E(null).instanceFun));
-    checks.add((x) {
-      Expect.equals(1234, (x as E).fun());
-    });
-  } else {
-    Expect.throws(() => ping.send(new E(new E(null).instanceFun)));
-  }
+  ping.send(new E(new E(null).instanceFun));
+  checks.add((x) {
+    Expect.equals(1234, (x as E).fun());
+  });
 
   F nonConstF = new F();
   ping.send(nonConstF);
diff --git a/tests/lib_2/isolate/message4_test.dart b/tests/lib_2/isolate/message4_test.dart
index 045cde1..425ebb6 100644
--- a/tests/lib_2/isolate/message4_test.dart
+++ b/tests/lib_2/isolate/message4_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing serialization of messages with static
 // native functions.
 
diff --git a/tests/lib_2/isolate/message_const_type_arguments_1_test.dart b/tests/lib_2/isolate/message_const_type_arguments_1_test.dart
index 8e3144e..c189ecf 100644
--- a/tests/lib_2/isolate/message_const_type_arguments_1_test.dart
+++ b/tests/lib_2/isolate/message_const_type_arguments_1_test.dart
@@ -4,14 +4,11 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // https://github.com/dart-lang/sdk/issues/35778
 
 import "dart:async";
 import "dart:isolate";
-import "dart:typed_data";
+
 import "package:expect/expect.dart";
 
 void child(replyPort) {
diff --git a/tests/lib_2/isolate/message_const_type_arguments_2_test.dart b/tests/lib_2/isolate/message_const_type_arguments_2_test.dart
index 87c76ab..cc2a7e3 100644
--- a/tests/lib_2/isolate/message_const_type_arguments_2_test.dart
+++ b/tests/lib_2/isolate/message_const_type_arguments_2_test.dart
@@ -4,14 +4,11 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // https://github.com/dart-lang/sdk/issues/35778
 
 import "dart:async";
 import "dart:isolate";
-import "dart:typed_data";
+
 import "package:expect/expect.dart";
 
 void child(replyPort) {
diff --git a/tests/lib_2/isolate/message_enum_test.dart b/tests/lib_2/isolate/message_enum_test.dart
index 5487f73..4c34b38 100644
--- a/tests/lib_2/isolate/message_enum_test.dart
+++ b/tests/lib_2/isolate/message_enum_test.dart
@@ -4,12 +4,10 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
+import "dart:isolate";
 
 import 'package:expect/expect.dart';
 import 'package:async_helper/async_helper.dart';
-import "dart:isolate";
 
 enum Foo { BAR, BAZ }
 
diff --git a/tests/lib_2/isolate/message_test.dart b/tests/lib_2/isolate/message_test.dart
index 7ca930a..8189027 100644
--- a/tests/lib_2/isolate/message_test.dart
+++ b/tests/lib_2/isolate/message_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing serialization of messages.
 // VMOptions=--enable_type_checks --enable_asserts
 
diff --git a/tests/lib_2/isolate/mint_maker_test.dart b/tests/lib_2/isolate/mint_maker_test.dart
index 9b1b15c..397d60b 100644
--- a/tests/lib_2/isolate/mint_maker_test.dart
+++ b/tests/lib_2/isolate/mint_maker_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library MintMakerTest;
 
 import 'dart:async';
diff --git a/tests/lib_2/isolate/native_wrapper_message_test.dart b/tests/lib_2/isolate/native_wrapper_message_test.dart
index 4c91d647..1cbf323 100644
--- a/tests/lib_2/isolate/native_wrapper_message_test.dart
+++ b/tests/lib_2/isolate/native_wrapper_message_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:isolate';
 import 'dart:nativewrappers';
 import 'package:expect/expect.dart';
diff --git a/tests/lib_2/isolate/nested_spawn2_test.dart b/tests/lib_2/isolate/nested_spawn2_test.dart
index 5c0c8be..9b93cb9 100644
--- a/tests/lib_2/isolate/nested_spawn2_test.dart
+++ b/tests/lib_2/isolate/nested_spawn2_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates can spawn other isolates and
 // that the nested isolates can communicate with the main once the spawner has
 // disappeared.
diff --git a/tests/lib_2/isolate/nested_spawn_test.dart b/tests/lib_2/isolate/nested_spawn_test.dart
index 050f383..4483df1 100644
--- a/tests/lib_2/isolate/nested_spawn_test.dart
+++ b/tests/lib_2/isolate/nested_spawn_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates can spawn other isolates.
 
 library NestedSpawnTest;
diff --git a/tests/lib_2/isolate/non_fatal_exception_in_timer_callback_test.dart b/tests/lib_2/isolate/non_fatal_exception_in_timer_callback_test.dart
index 03db0b8..d1a1d32 100644
--- a/tests/lib_2/isolate/non_fatal_exception_in_timer_callback_test.dart
+++ b/tests/lib_2/isolate/non_fatal_exception_in_timer_callback_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 import 'dart:io';
diff --git a/tests/lib_2/isolate/object_leak_test.dart b/tests/lib_2/isolate/object_leak_test.dart
index 719b8d8..8602ca0 100644
--- a/tests/lib_2/isolate/object_leak_test.dart
+++ b/tests/lib_2/isolate/object_leak_test.dart
@@ -4,17 +4,14 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test for http://dartbug.com/18942
 
 library LeakTest;
 
+import 'dart:isolate';
+
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
-import 'dart:isolate';
-import 'dart:async';
 
 class A {
   var x = 0;
diff --git a/tests/lib_2/isolate/ondone_test.dart b/tests/lib_2/isolate/ondone_test.dart
index bc5d363..1b8421f 100644
--- a/tests/lib_2/isolate/ondone_test.dart
+++ b/tests/lib_2/isolate/ondone_test.dart
@@ -4,11 +4,9 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
+
 import "package:async_helper/async_helper.dart";
 
 void isomain(SendPort replyPort) {
diff --git a/tests/lib_2/isolate/package_config_test.dart b/tests/lib_2/isolate/package_config_test.dart
index 264aba2..fe0725d 100644
--- a/tests/lib_2/isolate/package_config_test.dart
+++ b/tests/lib_2/isolate/package_config_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // VMOptions=--trace_shutdown
+
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib_2/isolate/package_resolve_test.dart b/tests/lib_2/isolate/package_resolve_test.dart
index c36c430..057c5df 100644
--- a/tests/lib_2/isolate/package_resolve_test.dart
+++ b/tests/lib_2/isolate/package_resolve_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib_2/isolate/package_root_test.dart b/tests/lib_2/isolate/package_root_test.dart
index a8ef249..0902696 100644
--- a/tests/lib_2/isolate/package_root_test.dart
+++ b/tests/lib_2/isolate/package_root_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib_2/isolate/pause_test.dart b/tests/lib_2/isolate/pause_test.dart
index 240229e..5649705 100644
--- a/tests/lib_2/isolate/pause_test.dart
+++ b/tests/lib_2/isolate/pause_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib_2/isolate/ping_pause_test.dart b/tests/lib_2/isolate/ping_pause_test.dart
index 2c14c4f..8f9ffa0 100644
--- a/tests/lib_2/isolate/ping_pause_test.dart
+++ b/tests/lib_2/isolate/ping_pause_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/ping_test.dart b/tests/lib_2/isolate/ping_test.dart
index 8f191b5..c182e48 100644
--- a/tests/lib_2/isolate/ping_test.dart
+++ b/tests/lib_2/isolate/ping_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "dart:async";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/port_test.dart b/tests/lib_2/isolate/port_test.dart
index b46a048..76e2411 100644
--- a/tests/lib_2/isolate/port_test.dart
+++ b/tests/lib_2/isolate/port_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test properties of ports.
 library PortTest;
 
diff --git a/tests/lib_2/isolate/raw_port_test.dart b/tests/lib_2/isolate/raw_port_test.dart
index 08c1cc9..0f4634f 100644
--- a/tests/lib_2/isolate/raw_port_test.dart
+++ b/tests/lib_2/isolate/raw_port_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test RawReceivePort.
 
 library raw_port_test;
diff --git a/tests/lib_2/isolate/regress_34752_test.dart b/tests/lib_2/isolate/regress_34752_test.dart
index 8fe3c74..c630609 100644
--- a/tests/lib_2/isolate/regress_34752_test.dart
+++ b/tests/lib_2/isolate/regress_34752_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 // Verifies that large BigInt can be passed through a message port and
 // simple arithmetic operations still work after that.
diff --git a/tests/lib_2/isolate/regress_flutter_22796_test.dart b/tests/lib_2/isolate/regress_flutter_22796_test.dart
index 72200b8..35fd6b3 100644
--- a/tests/lib_2/isolate/regress_flutter_22796_test.dart
+++ b/tests/lib_2/isolate/regress_flutter_22796_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Verifies that large typed data can be passed in a field through message port.
 // This is a regression test for
 // https://github.com/flutter/flutter/issues/22796.
diff --git a/tests/lib_2/isolate/request_reply_test.dart b/tests/lib_2/isolate/request_reply_test.dart
index a2a0f53..23e55ed 100644
--- a/tests/lib_2/isolate/request_reply_test.dart
+++ b/tests/lib_2/isolate/request_reply_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library RequestReplyTest;
 
 import 'dart:isolate';
diff --git a/tests/lib_2/isolate/resolve_package_uri_test.dart b/tests/lib_2/isolate/resolve_package_uri_test.dart
index ce53991..d47c9d7 100644
--- a/tests/lib_2/isolate/resolve_package_uri_test.dart
+++ b/tests/lib_2/isolate/resolve_package_uri_test.dart
@@ -4,13 +4,9 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Regression test for faulty encoding of `Isolate.resolvePackageUri` by
 // dart2js.
 
-import 'dart:async';
 import 'dart:isolate';
 
 main() {
diff --git a/tests/lib_2/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart b/tests/lib_2/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart
index c36c430..057c5df 100644
--- a/tests/lib_2/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart
+++ b/tests/lib_2/isolate/scenarios/package_data_uri_spec/package_resolve_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/lib_2/isolate/send_private_test.dart b/tests/lib_2/isolate/send_private_test.dart
index 645c12b..f265187 100644
--- a/tests/lib_2/isolate/send_private_test.dart
+++ b/tests/lib_2/isolate/send_private_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 import "package:expect/expect.dart";
 
diff --git a/tests/lib_2/isolate/simple_message_test.dart b/tests/lib_2/isolate/simple_message_test.dart
index f5a394c..6cd8da0 100644
--- a/tests/lib_2/isolate/simple_message_test.dart
+++ b/tests/lib_2/isolate/simple_message_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Dart test program for testing that isolates are spawned.
 
 library IsolateNegativeTest;
diff --git a/tests/lib_2/isolate/spawn_function_custom_class_test.dart b/tests/lib_2/isolate/spawn_function_custom_class_test.dart
index 0e9ad2b..fbbdf69 100644
--- a/tests/lib_2/isolate/spawn_function_custom_class_test.dart
+++ b/tests/lib_2/isolate/spawn_function_custom_class_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Create a user-defined class in a new isolate.
 //
 // Regression test for vm bug 2235: We were forgetting to finalize
diff --git a/tests/lib_2/isolate/spawn_function_test.dart b/tests/lib_2/isolate/spawn_function_test.dart
index b12246e..5071ffa 100644
--- a/tests/lib_2/isolate/spawn_function_test.dart
+++ b/tests/lib_2/isolate/spawn_function_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of spawning an isolate from a function.
 library spawn_tests;
 
diff --git a/tests/lib_2/isolate/spawn_generic_test.dart b/tests/lib_2/isolate/spawn_generic_test.dart
index 05ea808..7305917 100644
--- a/tests/lib_2/isolate/spawn_generic_test.dart
+++ b/tests/lib_2/isolate/spawn_generic_test.dart
@@ -4,16 +4,13 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Check that Isolate.spawn is generic.
 library spawn_generic;
 
 import "dart:isolate";
 import "dart:async";
+
 import "package:async_helper/async_helper.dart";
-import "package:expect/expect.dart";
 
 void isomain(num args) {
   print(args);
diff --git a/tests/lib_2/isolate/spawn_uri_exported_main_test.dart b/tests/lib_2/isolate/spawn_uri_exported_main_test.dart
index 463181f..d378cb0 100644
--- a/tests/lib_2/isolate/spawn_uri_exported_main_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_exported_main_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:isolate";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/spawn_uri_fail_test.dart b/tests/lib_2/isolate/spawn_uri_fail_test.dart
index 9b5346f..45b39ba 100644
--- a/tests/lib_2/isolate/spawn_uri_fail_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_fail_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:io";
 import "dart:isolate";
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/spawn_uri_missing_from_isolate_test.dart b/tests/lib_2/isolate/spawn_uri_missing_from_isolate_test.dart
index 204fa9c..dfd0305 100644
--- a/tests/lib_2/isolate/spawn_uri_missing_from_isolate_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_missing_from_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 /// Tests that Isolate.spawnUri completes with an error when the given URI
 /// doesn't resolve to an existing resource.
 ///
diff --git a/tests/lib_2/isolate/spawn_uri_missing_test.dart b/tests/lib_2/isolate/spawn_uri_missing_test.dart
index fe27ff0..99e70b0 100644
--- a/tests/lib_2/isolate/spawn_uri_missing_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_missing_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 /// Tests that Isolate.spanUri completes with an error when the given URI
 /// doesn't resolve to an existing resource.
 library test.isolate.spawn_uri_missing_test;
diff --git a/tests/lib_2/isolate/spawn_uri_multi_test.dart b/tests/lib_2/isolate/spawn_uri_multi_test.dart
index dc50328..7d22284 100644
--- a/tests/lib_2/isolate/spawn_uri_multi_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_multi_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Negative test to make sure that we are reaching all assertions.
 library spawn_tests;
 
diff --git a/tests/lib_2/isolate/spawn_uri_nested_vm_test.dart b/tests/lib_2/isolate/spawn_uri_nested_vm_test.dart
index 81e5882..facefde 100644
--- a/tests/lib_2/isolate/spawn_uri_nested_vm_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_nested_vm_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of nested spawning of isolates from a URI
 library NestedSpawnUriLibrary;
 
diff --git a/tests/lib_2/isolate/spawn_uri_test.dart b/tests/lib_2/isolate/spawn_uri_test.dart
index 88e99bf..e85fbc6 100644
--- a/tests/lib_2/isolate/spawn_uri_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of spawning an isolate from a URI
 library spawn_tests;
 
diff --git a/tests/lib_2/isolate/spawn_uri_vm_test.dart b/tests/lib_2/isolate/spawn_uri_vm_test.dart
index 536b912..429b62b 100644
--- a/tests/lib_2/isolate/spawn_uri_vm_test.dart
+++ b/tests/lib_2/isolate/spawn_uri_vm_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Example of spawning an isolate from a URI
 library spawn_tests;
 
diff --git a/tests/lib_2/isolate/start_paused_test.dart b/tests/lib_2/isolate/start_paused_test.dart
index 7ee4993..e066a93 100644
--- a/tests/lib_2/isolate/start_paused_test.dart
+++ b/tests/lib_2/isolate/start_paused_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library start_paused_test;
 
 import "dart:isolate";
diff --git a/tests/lib_2/isolate/static_function_test.dart b/tests/lib_2/isolate/static_function_test.dart
index 23a18fe..cccae39 100644
--- a/tests/lib_2/isolate/static_function_test.dart
+++ b/tests/lib_2/isolate/static_function_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // Test starting isolate with static functions (and toplevel ones, for sanity).
 
 library static_function_test;
@@ -118,9 +115,6 @@
 }
 
 void main([args, port]) {
-  final bool isolateGroupsEnabled =
-      Platform.executableArguments.contains('--enable-isolate-groups');
-
   asyncStart();
   // Sanity check.
   spawnTest("function", function, "TOP");
@@ -140,31 +134,17 @@
   spawnTest("lib._class._function", lib.privateClassFunction, "_LIB");
   spawnTest("lib._class._function", lib.privateClassAndFunction, "_LIBPRIVATE");
 
-  if (isolateGroupsEnabled) {
-    spawnTest("static closure", staticClosure, "WHAT?");
-    spawnTest("dynamic closure", dynamicClosure, "WHAT??");
-    spawnTest("named dynamic closure", namedDynamicClosure, "WHAT FOO??");
-    spawnTest("instance closure", new C().instanceClosure, "C WHAT?");
-    spawnTest(
-        "initializer closure", new C().constructorInitializerClosure, "Init?");
-    spawnTest(
-        "constructor closure", new C().constructorBodyClosure, "bodyClosure?");
-    spawnTest("named constructor closure", new C().namedConstructorBodyClosure,
-        "namedBodyClosure?");
-    spawnTest("instance method", new C().instanceMethod, "INSTANCE WHAT?");
-  } else {
-    // Negative tests
-    functionFailTest("static closure", staticClosure);
-    functionFailTest("dynamic closure", dynamicClosure);
-    functionFailTest("named dynamic closure", namedDynamicClosure);
-    functionFailTest("instance closure", new C().instanceClosure);
-    functionFailTest(
-        "initializer closure", new C().constructorInitializerClosure);
-    functionFailTest("constructor closure", new C().constructorBodyClosure);
-    functionFailTest(
-        "named constructor closure", new C().namedConstructorBodyClosure);
-    functionFailTest("instance method", new C().instanceMethod);
-  }
+  spawnTest("static closure", staticClosure, "WHAT?");
+  spawnTest("dynamic closure", dynamicClosure, "WHAT??");
+  spawnTest("named dynamic closure", namedDynamicClosure, "WHAT FOO??");
+  spawnTest("instance closure", new C().instanceClosure, "C WHAT?");
+  spawnTest(
+      "initializer closure", new C().constructorInitializerClosure, "Init?");
+  spawnTest(
+      "constructor closure", new C().constructorBodyClosure, "bodyClosure?");
+  spawnTest("named constructor closure", new C().namedConstructorBodyClosure,
+      "namedBodyClosure?");
+  spawnTest("instance method", new C().instanceMethod, "INSTANCE WHAT?");
 
   asyncEnd();
 }
diff --git a/tests/lib_2/isolate/string_from_environment_default_value_test.dart b/tests/lib_2/isolate/string_from_environment_default_value_test.dart
index f920f65..1a9a550 100644
--- a/tests/lib_2/isolate/string_from_environment_default_value_test.dart
+++ b/tests/lib_2/isolate/string_from_environment_default_value_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:expect/expect.dart";
diff --git a/tests/lib_2/isolate/timer_isolate_test.dart b/tests/lib_2/isolate/timer_isolate_test.dart
index 07485a6..9f87aa5 100644
--- a/tests/lib_2/isolate/timer_isolate_test.dart
+++ b/tests/lib_2/isolate/timer_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library multiple_timer_test;
 
 import 'dart:isolate';
diff --git a/tests/lib_2/isolate/timer_multiple_isolates_test.dart b/tests/lib_2/isolate/timer_multiple_isolates_test.dart
index 0321a8b..d8b6fb7 100644
--- a/tests/lib_2/isolate/timer_multiple_isolates_test.dart
+++ b/tests/lib_2/isolate/timer_multiple_isolates_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library timer_multiple_isolates_test;
 
 import 'dart:isolate';
diff --git a/tests/lib_2/isolate/transferable_failed_to_send_test.dart b/tests/lib_2/isolate/transferable_failed_to_send_test.dart
index 8f33958..b0ac3f4 100644
--- a/tests/lib_2/isolate/transferable_failed_to_send_test.dart
+++ b/tests/lib_2/isolate/transferable_failed_to_send_test.dart
@@ -4,16 +4,14 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:io" show ServerSocket;
 import "dart:isolate";
 import "dart:typed_data" show ByteData;
 
 import "package:expect/expect.dart";
-import "package:async_helper/async_helper.dart";
 
 void main() async {
   final port = new ReceivePort();
diff --git a/tests/lib_2/isolate/transferable_test.dart b/tests/lib_2/isolate/transferable_test.dart
index 26cb2e0..5d8ed4d 100644
--- a/tests/lib_2/isolate/transferable_test.dart
+++ b/tests/lib_2/isolate/transferable_test.dart
@@ -4,9 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups --no-enable-fast-object-copy
-// VMOptions=--enable-isolate-groups --enable-fast-object-copy
-// VMOptions=--no-enable-isolate-groups
+// VMOptions=--no-enable-fast-object-copy
+// VMOptions=--enable-fast-object-copy
 
 import "dart:async";
 import "dart:collection";
diff --git a/tests/lib_2/isolate/typed_message_test.dart b/tests/lib_2/isolate/typed_message_test.dart
index 3b30415..77c76d0 100644
--- a/tests/lib_2/isolate/typed_message_test.dart
+++ b/tests/lib_2/isolate/typed_message_test.dart
@@ -4,8 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
 // Dart test program for testing isolate communication with
 // typed objects.
 
diff --git a/tests/lib_2/isolate/unresolved_ports_test.dart b/tests/lib_2/isolate/unresolved_ports_test.dart
index 408a26e..5147909 100644
--- a/tests/lib_2/isolate/unresolved_ports_test.dart
+++ b/tests/lib_2/isolate/unresolved_ports_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 // spawns multiple isolates and sends unresolved ports between them.
 library unresolved_ports;
 
diff --git a/tests/lib_2/isolate/vm_rehash_test.dart b/tests/lib_2/isolate/vm_rehash_test.dart
index 3813b67..2709901 100644
--- a/tests/lib_2/isolate/vm_rehash_test.dart
+++ b/tests/lib_2/isolate/vm_rehash_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
 
diff --git a/tests/lib_2/isolate/weak_property_message_1_test.dart b/tests/lib_2/isolate/weak_property_message_1_test.dart
index b58e261..f5889fb 100644
--- a/tests/lib_2/isolate/weak_property_message_1_test.dart
+++ b/tests/lib_2/isolate/weak_property_message_1_test.dart
@@ -6,9 +6,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups
-
 import "dart:isolate";
 
 import "package:async_helper/async_helper.dart";
diff --git a/tests/lib_2/isolate/weak_property_message_2_test.dart b/tests/lib_2/isolate/weak_property_message_2_test.dart
index 353a8f5..517ae34 100644
--- a/tests/lib_2/isolate/weak_property_message_2_test.dart
+++ b/tests/lib_2/isolate/weak_property_message_2_test.dart
@@ -6,9 +6,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--no-enable-isolate-groups
-// VMOptions=--enable-isolate-groups
-
 import "dart:developer";
 import "dart:isolate";
 
diff --git a/tests/standalone/io/echo_server_stream_test.dart b/tests/standalone/io/echo_server_stream_test.dart
index 6da8ca2..ffbeba2 100644
--- a/tests/standalone/io/echo_server_stream_test.dart
+++ b/tests/standalone/io/echo_server_stream_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Echo server test program to test socket streams.
 //
 // VMOptions=
diff --git a/tests/standalone/io/file_system_watcher_large_set_test.dart b/tests/standalone/io/file_system_watcher_large_set_test.dart
index 2a4ed9d..07873a7 100644
--- a/tests/standalone/io/file_system_watcher_large_set_test.dart
+++ b/tests/standalone/io/file_system_watcher_large_set_test.dart
@@ -2,8 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--delayed-filewatch-callback --enable-isolate-groups
-// VMOptions=--delayed-filewatch-callback --no-enable-isolate-groups
+// VMOptions=--delayed-filewatch-callback
 
 // Verifies that cancelling subscription from inside of the event handler
 // works as expected, does not result in crash or hang.
diff --git a/tests/standalone/io/file_system_watcher_test.dart b/tests/standalone/io/file_system_watcher_test.dart
index dae7f9d..e629e56 100644
--- a/tests/standalone/io/file_system_watcher_test.dart
+++ b/tests/standalone/io/file_system_watcher_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
diff --git a/tests/standalone/io/http_advanced_test.dart b/tests/standalone/io/http_advanced_test.dart
index 87553d9..344e0da 100644
--- a/tests/standalone/io/http_advanced_test.dart
+++ b/tests/standalone/io/http_advanced_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
diff --git a/tests/standalone/io/http_basic_test.dart b/tests/standalone/io/http_basic_test.dart
index acc6eb5..9d001b0 100644
--- a/tests/standalone/io/http_basic_test.dart
+++ b/tests/standalone/io/http_basic_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=--trace_shutdown
 // VMOptions=--trace_shutdown --short_socket_read
 // VMOptions=--trace_shutdown --short_socket_write
diff --git a/tests/standalone/io/http_read_test.dart b/tests/standalone/io/http_read_test.dart
index b6f4a7e..584a7e1 100644
--- a/tests/standalone/io/http_read_test.dart
+++ b/tests/standalone/io/http_read_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
diff --git a/tests/standalone/io/pipe_server_test.dart b/tests/standalone/io/pipe_server_test.dart
index 52d93b6..c2a1b93 100644
--- a/tests/standalone/io/pipe_server_test.dart
+++ b/tests/standalone/io/pipe_server_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // OtherResources=readline_test1.dat
 //
 // VMOptions=
diff --git a/tests/standalone/io/platform_test.dart b/tests/standalone/io/platform_test.dart
index ace9d85..dacd0a8 100644
--- a/tests/standalone/io/platform_test.dart
+++ b/tests/standalone/io/platform_test.dart
@@ -2,10 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
-import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
diff --git a/tests/standalone/io/raw_synchronous_socket_test.dart b/tests/standalone/io/raw_synchronous_socket_test.dart
index 50cb0f2..96f4511 100644
--- a/tests/standalone/io/raw_synchronous_socket_test.dart
+++ b/tests/standalone/io/raw_synchronous_socket_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
diff --git a/tests/standalone/io/shared_socket_test.dart b/tests/standalone/io/shared_socket_test.dart
index 3195b63..39eb4d1 100644
--- a/tests/standalone/io/shared_socket_test.dart
+++ b/tests/standalone/io/shared_socket_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
diff --git a/tests/standalone/io/socket_close_test.dart b/tests/standalone/io/socket_close_test.dart
index 72a15de..38cc0d6 100644
--- a/tests/standalone/io/socket_close_test.dart
+++ b/tests/standalone/io/socket_close_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
diff --git a/tests/standalone/io/socket_finalizer_test.dart b/tests/standalone/io/socket_finalizer_test.dart
index c82be22..5dfca94 100644
--- a/tests/standalone/io/socket_finalizer_test.dart
+++ b/tests/standalone/io/socket_finalizer_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // This test checks that sockets belonging to an isolate are properly cleaned up
 // when the isolate shuts down abnormally. If the socket is not properly cleaned
 // up, the test will time out.
diff --git a/tests/standalone/io/socket_many_connections_test.dart b/tests/standalone/io/socket_many_connections_test.dart
index 0140df7..5ed8d9d1 100644
--- a/tests/standalone/io/socket_many_connections_test.dart
+++ b/tests/standalone/io/socket_many_connections_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Test creating a large number of socket connections.
 library ServerTest;
 
diff --git a/tests/standalone/io/stdio_socket_finalizer_test.dart b/tests/standalone/io/stdio_socket_finalizer_test.dart
index c33da51..a35f0d5 100644
--- a/tests/standalone/io/stdio_socket_finalizer_test.dart
+++ b/tests/standalone/io/stdio_socket_finalizer_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // This test checks that stdin is *not* closed when an Isolate leaks it.
 
 import 'dart:async';
diff --git a/tests/standalone/io/wait_for_event_isolate_test.dart b/tests/standalone/io/wait_for_event_isolate_test.dart
index ce624e2..5948ea3 100644
--- a/tests/standalone/io/wait_for_event_isolate_test.dart
+++ b/tests/standalone/io/wait_for_event_isolate_test.dart
@@ -2,12 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
-import 'dart:cli';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
diff --git a/tests/standalone/packages_file_test.dart b/tests/standalone/packages_file_test.dart
index 99c2ab5..57fe3bf 100644
--- a/tests/standalone/packages_file_test.dart
+++ b/tests/standalone/packages_file_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:io";
 import "dart:convert" show json;
@@ -986,8 +983,7 @@
         "  config: $config\n"
         "  main  : $mainFile\n"
         "  args  : ${args.map((x) => '"$x"').join(" ")}\n"
-        ") : expect {\n${expect.keys.map((k) =>
-           '  "$k"'.padRight(6) + ":${json.encode(expect[k])}\n").join()}"
+        ") : expect {\n${expect.keys.map((k) => '  "$k"'.padRight(6) + ":${json.encode(expect[k])}\n").join()}"
         "}";
   }
 }
diff --git a/tests/standalone/regress_26031_test.dart b/tests/standalone/regress_26031_test.dart
index 60dd89b..c8a8e0a 100644
--- a/tests/standalone/regress_26031_test.dart
+++ b/tests/standalone/regress_26031_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/standalone/regress_28854_1_test.dart b/tests/standalone/regress_28854_1_test.dart
index 30b304a..80c831b 100644
--- a/tests/standalone/regress_28854_1_test.dart
+++ b/tests/standalone/regress_28854_1_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library regress;
 
 import 'dart:isolate';
diff --git a/tests/standalone/regress_28854_2_test.dart b/tests/standalone/regress_28854_2_test.dart
index 21395c1..169bb09 100644
--- a/tests/standalone/regress_28854_2_test.dart
+++ b/tests/standalone/regress_28854_2_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library regress;
 
 import 'dart:isolate';
diff --git a/tests/standalone/typed_array_int64_uint64_test.dart b/tests/standalone/typed_array_int64_uint64_test.dart
index 7b57986..e22036b 100644
--- a/tests/standalone/typed_array_int64_uint64_test.dart
+++ b/tests/standalone/typed_array_int64_uint64_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Dart test program for testing native typed arrays, int64 and uint64 only.
 
 // Library tag to be able to run in html test framework.
diff --git a/tests/standalone/typed_array_test.dart b/tests/standalone/typed_array_test.dart
index 6e4c6c3..305d736 100644
--- a/tests/standalone/typed_array_test.dart
+++ b/tests/standalone/typed_array_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Dart test program for testing native float and int arrays.  64-bit int arrays
 // are in a separate test.
 
diff --git a/tests/standalone/typed_data_isolate_test.dart b/tests/standalone/typed_data_isolate_test.dart
index 2573ada..a95b9db 100644
--- a/tests/standalone/typed_data_isolate_test.dart
+++ b/tests/standalone/typed_data_isolate_test.dart
@@ -2,9 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Dart test program for testing typed data.
 
 // Library tag to be able to run in html test framework.
diff --git a/tests/standalone_2/io/echo_server_stream_test.dart b/tests/standalone_2/io/echo_server_stream_test.dart
index e0449a3..1cfb36d 100644
--- a/tests/standalone_2/io/echo_server_stream_test.dart
+++ b/tests/standalone_2/io/echo_server_stream_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Echo server test program to test socket streams.
 //
 // VMOptions=
diff --git a/tests/standalone_2/io/file_system_watcher_large_set_test.dart b/tests/standalone_2/io/file_system_watcher_large_set_test.dart
index 326d201..9240759 100644
--- a/tests/standalone_2/io/file_system_watcher_large_set_test.dart
+++ b/tests/standalone_2/io/file_system_watcher_large_set_test.dart
@@ -2,8 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// VMOptions=--delayed-filewatch-callback --enable-isolate-groups
-// VMOptions=--delayed-filewatch-callback --no-enable-isolate-groups
+// VMOptions=--delayed-filewatch-callback
 
 // Verifies that cancelling subscription from inside of the event handler
 // works as expected, does not result in crash or hang.
diff --git a/tests/standalone_2/io/file_system_watcher_test.dart b/tests/standalone_2/io/file_system_watcher_test.dart
index bde35ce..b3e79db 100644
--- a/tests/standalone_2/io/file_system_watcher_test.dart
+++ b/tests/standalone_2/io/file_system_watcher_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
diff --git a/tests/standalone_2/io/http_advanced_test.dart b/tests/standalone_2/io/http_advanced_test.dart
index 10b6a5b..0d5c80f 100644
--- a/tests/standalone_2/io/http_advanced_test.dart
+++ b/tests/standalone_2/io/http_advanced_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
diff --git a/tests/standalone_2/io/http_basic_test.dart b/tests/standalone_2/io/http_basic_test.dart
index 1cae05b..8d96875 100644
--- a/tests/standalone_2/io/http_basic_test.dart
+++ b/tests/standalone_2/io/http_basic_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=--trace_shutdown
 // VMOptions=--trace_shutdown --short_socket_read
 // VMOptions=--trace_shutdown --short_socket_write
diff --git a/tests/standalone_2/io/http_read_test.dart b/tests/standalone_2/io/http_read_test.dart
index 120e9ff..cc42d71 100644
--- a/tests/standalone_2/io/http_read_test.dart
+++ b/tests/standalone_2/io/http_read_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
diff --git a/tests/standalone_2/io/pipe_server_test.dart b/tests/standalone_2/io/pipe_server_test.dart
index 4628c69..f01e9c1 100644
--- a/tests/standalone_2/io/pipe_server_test.dart
+++ b/tests/standalone_2/io/pipe_server_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // OtherResources=readline_test1.dat
 //
 // VMOptions=
diff --git a/tests/standalone_2/io/platform_test.dart b/tests/standalone_2/io/platform_test.dart
index 2ddc45d..dfe18ba 100644
--- a/tests/standalone_2/io/platform_test.dart
+++ b/tests/standalone_2/io/platform_test.dart
@@ -4,10 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
-import "dart:async";
 import "dart:io";
 import "dart:isolate";
 
diff --git a/tests/standalone_2/io/raw_synchronous_socket_test.dart b/tests/standalone_2/io/raw_synchronous_socket_test.dart
index 9e5b6bb..3e8a86b 100644
--- a/tests/standalone_2/io/raw_synchronous_socket_test.dart
+++ b/tests/standalone_2/io/raw_synchronous_socket_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
diff --git a/tests/standalone_2/io/shared_socket_test.dart b/tests/standalone_2/io/shared_socket_test.dart
index 6a12132..6cf7641 100644
--- a/tests/standalone_2/io/shared_socket_test.dart
+++ b/tests/standalone_2/io/shared_socket_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
diff --git a/tests/standalone_2/io/socket_close_test.dart b/tests/standalone_2/io/socket_close_test.dart
index f9ad2d0..f509bc4 100644
--- a/tests/standalone_2/io/socket_close_test.dart
+++ b/tests/standalone_2/io/socket_close_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // VMOptions=
 // VMOptions=--short_socket_read
 // VMOptions=--short_socket_write
diff --git a/tests/standalone_2/io/socket_finalizer_test.dart b/tests/standalone_2/io/socket_finalizer_test.dart
index ecd8de3..a449270 100644
--- a/tests/standalone_2/io/socket_finalizer_test.dart
+++ b/tests/standalone_2/io/socket_finalizer_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // This test checks that sockets belonging to an isolate are properly cleaned up
 // when the isolate shuts down abnormally. If the socket is not properly cleaned
 // up, the test will time out.
diff --git a/tests/standalone_2/io/socket_many_connections_test.dart b/tests/standalone_2/io/socket_many_connections_test.dart
index 0e665dc..4944c33 100644
--- a/tests/standalone_2/io/socket_many_connections_test.dart
+++ b/tests/standalone_2/io/socket_many_connections_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Test creating a large number of socket connections.
 library ServerTest;
 
diff --git a/tests/standalone_2/io/stdio_socket_finalizer_test.dart b/tests/standalone_2/io/stdio_socket_finalizer_test.dart
index 7cc1b64..1a36dd8 100644
--- a/tests/standalone_2/io/stdio_socket_finalizer_test.dart
+++ b/tests/standalone_2/io/stdio_socket_finalizer_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // This test checks that stdin is *not* closed when an Isolate leaks it.
 
 import 'dart:async';
diff --git a/tests/standalone_2/io/wait_for_event_isolate_test.dart b/tests/standalone_2/io/wait_for_event_isolate_test.dart
index a22ce25..7cad2c2 100644
--- a/tests/standalone_2/io/wait_for_event_isolate_test.dart
+++ b/tests/standalone_2/io/wait_for_event_isolate_test.dart
@@ -4,12 +4,8 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:async';
 import 'dart:isolate';
-import 'dart:cli';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
diff --git a/tests/standalone_2/packages_file_test.dart b/tests/standalone_2/packages_file_test.dart
index a527ab4..26f9346 100644
--- a/tests/standalone_2/packages_file_test.dart
+++ b/tests/standalone_2/packages_file_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import "dart:async";
 import "dart:io";
 import "dart:convert" show json;
@@ -988,8 +985,7 @@
         "  config: $config\n"
         "  main  : $mainFile\n"
         "  args  : ${args.map((x) => '"$x"').join(" ")}\n"
-        ") : expect {\n${expect.keys.map((k) =>
-           '  "$k"'.padRight(6) + ":${json.encode(expect[k])}\n").join()}"
+        ") : expect {\n${expect.keys.map((k) => '  "$k"'.padRight(6) + ":${json.encode(expect[k])}\n").join()}"
         "}";
   }
 }
diff --git a/tests/standalone_2/regress_26031_test.dart b/tests/standalone_2/regress_26031_test.dart
index 933f5b9..0c7b705 100644
--- a/tests/standalone_2/regress_26031_test.dart
+++ b/tests/standalone_2/regress_26031_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 import 'dart:io';
 import 'dart:isolate';
 
diff --git a/tests/standalone_2/regress_28854_1_test.dart b/tests/standalone_2/regress_28854_1_test.dart
index fdc3cc1..f2c7cba 100644
--- a/tests/standalone_2/regress_28854_1_test.dart
+++ b/tests/standalone_2/regress_28854_1_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library regress;
 
 import 'dart:isolate';
diff --git a/tests/standalone_2/regress_28854_2_test.dart b/tests/standalone_2/regress_28854_2_test.dart
index d05b294..24d6282 100644
--- a/tests/standalone_2/regress_28854_2_test.dart
+++ b/tests/standalone_2/regress_28854_2_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-
 library regress;
 
 import 'dart:isolate';
diff --git a/tests/standalone_2/typed_array_int64_uint64_test.dart b/tests/standalone_2/typed_array_int64_uint64_test.dart
index 3eb3833..c394748 100644
--- a/tests/standalone_2/typed_array_int64_uint64_test.dart
+++ b/tests/standalone_2/typed_array_int64_uint64_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Dart test program for testing native typed arrays, int64 and uint64 only.
 
 // Library tag to be able to run in html test framework.
diff --git a/tests/standalone_2/typed_array_test.dart b/tests/standalone_2/typed_array_test.dart
index 94be7ec..9557f01b 100644
--- a/tests/standalone_2/typed_array_test.dart
+++ b/tests/standalone_2/typed_array_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Dart test program for testing native float and int arrays.  64-bit int arrays
 // are in a separate test.
 
diff --git a/tests/standalone_2/typed_data_isolate_test.dart b/tests/standalone_2/typed_data_isolate_test.dart
index 0868696..c3b4c30 100644
--- a/tests/standalone_2/typed_data_isolate_test.dart
+++ b/tests/standalone_2/typed_data_isolate_test.dart
@@ -4,9 +4,6 @@
 
 // @dart = 2.9
 
-// VMOptions=--enable-isolate-groups
-// VMOptions=--no-enable-isolate-groups
-//
 // Dart test program for testing typed data.
 
 // Library tag to be able to run in html test framework.