Fix some service protocol isolate lifecycle races

runtime/vm/service_event.h

Index: runtime/vm/service_event.h
diff --git a/runtime/vm/service_event.h b/runtime/vm/service_event.h
index e5afb6d0deb5f857733c9580adaedec4a4ebf416..90f3893a7a445613faa2594905da50bf5d898d02 100644
--- a/runtime/vm/service_event.h
+++ b/runtime/vm/service_event.h
@@ -28,6 +28,7 @@ class ServiceEvent {
     kPauseBreakpoint,
     kPauseInterrupted,
     kPauseException,
+    kPauseUntilRunnable,  // isolate has not been made runnable yet.
     kResume,
     kBreakpointAdded,
     kBreakpointResolved,
@@ -77,6 +78,7 @@ class ServiceEvent {
       case kPauseBreakpoint:
       case kPauseInterrupted:
       case kPauseException:
+      case kPauseUntilRunnable:
         return true;
       default:
         return false;