Fix for use-after-free of reload context

runtime/vm/isolate.h

Index: runtime/vm/isolate.h
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index a43a543cfc2312246af5cfac6cb1cc10490398a9..b49d59b130bf265f9f316dee4d2d03b39ab94e08 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -255,7 +255,9 @@ class Isolate : public BaseIsolate {
   void DoneLoading();
   void DoneFinalizing();
 
-  void ReloadSources(bool test_mode = false);
+  // By default the reload context is deleted. This parameter allows
+  // the caller to delete is separately if it is still needed.
+  void ReloadSources(bool dont_delete_reload_context = false);
 
   bool MakeRunnable();
   void Run();
@@ -480,6 +482,8 @@ class Isolate : public BaseIsolate {
     return reload_context_;
   }
 
+  void DeleteReloadContext();
+
   bool HasAttemptedReload() const {
     return has_attempted_reload_;
   }