VM: Remove unnecessary imports

TEST=Existing tests on existing bots

Bug: https://github.com/dart-lang/sdk/issues/44569
Change-Id: I0c8ee9afa85da3a1a39a983841e62956e76dd509
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/177242
Commit-Queue: Samuel Rawlins <srawlins@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>
diff --git a/pkg/vm/bin/kernel_service.dart b/pkg/vm/bin/kernel_service.dart
index 13aa646..3a7d5f4 100644
--- a/pkg/vm/bin/kernel_service.dart
+++ b/pkg/vm/bin/kernel_service.dart
@@ -44,8 +44,6 @@
     show autoDetectNullSafetyMode, createLoadedLibrariesSet;
 import 'package:vm/http_filesystem.dart';
 import 'package:vm/target/vm.dart' show VmTarget;
-import 'package:front_end/src/api_prototype/compiler_options.dart'
-    show CompilerOptions, parseExperimentalFlags;
 
 final bool verbose = new bool.fromEnvironment('DFE_VERBOSE');
 final bool dumpKernel = new bool.fromEnvironment('DFE_DUMP_KERNEL');