Revert VM thread cleanup

runtime/bin/vmservice/vmservice_io.dart

Index: runtime/bin/vmservice/vmservice_io.dart
diff --git a/runtime/bin/vmservice/vmservice_io.dart b/runtime/bin/vmservice/vmservice_io.dart
index d9b0c754f1735b403314209d7a5968e382249799..409bc5972a0c110d842c0da006e319a958bef8ff 100644
--- a/runtime/bin/vmservice/vmservice_io.dart
+++ b/runtime/bin/vmservice/vmservice_io.dart
@@ -89,15 +89,6 @@ main() {
     // scheduled microtasks.
     Timer.run(() {});
   }
-  // TODO(johnmccutchan, turnidge) Creating a VMService object here causes
-  // strange behavior from the legacy debug protocol and coverage tool.
-  // Enable this code, and remove the call to Isolate::KillIsolate() from
-  // service_isolate.cc when the strange behavior is solved.
-  // See: https://github.com/dart-lang/sdk/issues/23977
-  // else {
-  //   var service = new VMService();
-  //   service.onShutdown = _onShutdown;
-  // }
   scriptLoadPort.handler = _processLoadRequest;
   // Register signal handler after a small delay to avoid stalling main
   // isolate startup.