Fix language_2/vm/optimized_guarded_field_isolates_test

This fixes some hot reload/rollback builders.

Issue https://github.com/dart-lang/sdk/issues/31402

Change-Id: I6f9f3c80f1f70b0f7084bd0c162affa125f43ba1
Reviewed-on: https://dart-review.googlesource.com/60963
Reviewed-by: Martin Kustermann <kustermann@google.com>
diff --git a/tests/language_2/language_2_kernel.status b/tests/language_2/language_2_kernel.status
index 4d391b5..44216f1 100644
--- a/tests/language_2/language_2_kernel.status
+++ b/tests/language_2/language_2_kernel.status
@@ -166,7 +166,6 @@
 type_promotion_functions_test/14: CompileTimeError
 type_promotion_functions_test/none: CompileTimeError
 type_promotion_more_specific_test/04: CompileTimeError
-vm/optimized_guarded_field_isolates_test: RuntimeError
 vm/type_cast_vm_test: RuntimeError
 
 [ $compiler == dartkp ]
@@ -843,7 +842,6 @@
 type_promotion_logical_and_test/01: MissingCompileTimeError
 type_promotion_more_specific_test/04: CompileTimeError # Issue 31533
 vm/closure_memory_retention_test: Skip # KernelVM bug: Hits OOM
-vm/optimized_guarded_field_isolates_test: RuntimeError # Issue 31402 (Variable declaration)
 vm/regress_29145_test: Skip # Issue 29145
 vm/type_cast_vm_test: RuntimeError
 void_block_return_test/00: MissingCompileTimeError
@@ -1205,7 +1203,6 @@
 vm/causal_async_exception_stack2_test: SkipByDesign
 vm/causal_async_exception_stack_test: SkipByDesign
 vm/closure_memory_retention_test: Skip # KernelVM bug: Hits OOM
-vm/optimized_guarded_field_isolates_test: RuntimeError
 vm/optimized_stacktrace_test: Crash
 vm/optimized_stacktrace_test: Skip # Issue 30198
 vm/reflect_core_vm_test: SkipByDesign
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 763dd12..8e68120 100644
--- a/tests/language_2/vm/optimized_guarded_field_isolates_test.dart
+++ b/tests/language_2/vm/optimized_guarded_field_isolates_test.dart
@@ -37,9 +37,9 @@
     test_b(b);
   }
   Expect.equals(3, test_b(b));
-  Future<B> item = receive_port.first;
-  item.then((B value) {
-    Expect.equals("foobar", test_b(value));
+  Future item = receive_port.first;
+  item.then((value) {
+    Expect.equals("foobar", test_b(value as B));
     receive_port.close();
     asyncEnd();
   });
@@ -65,9 +65,9 @@
     test_c(c);
   }
   Expect.equals(null, test_c(c));
-  Future<C> item = receive_port.first;
-  item.then((C value) {
-    Expect.throwsRangeError(() => test_c(value));
+  Future item = receive_port.first;
+  item.then((value) {
+    Expect.throwsRangeError(() => test_c(value as C));
     receive_port.close();
     asyncEnd();
   });