VM: Fix an app-jit related shutdown race.

runtime/bin/isolate_data.h

Index: runtime/bin/isolate_data.h
diff --git a/runtime/bin/isolate_data.h b/runtime/bin/isolate_data.h
index fea458cc4ecafe47832a8ed15c91f92720bc18ae..792f8935bebe860926c0667e8141947d3bd24780 100644
--- a/runtime/bin/isolate_data.h
+++ b/runtime/bin/isolate_data.h
@@ -68,6 +68,8 @@ class IsolateData {
     dependencies_ = deps;
   }
 
+  void OnIsolateShutdown();
+
  private:
   Dart_Handle builtin_lib_;
   Loader* loader_;