Fix failing tests and rollback two from Testing change for failing unit test

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index 1afbfc10681994c22f1043aa2e93165a6751ffaa..5d386cc04be6005c24b885f75f5133d814bca0ae 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -1787,9 +1787,7 @@ void Debug::FramesHaveBeenDropped(StackFrame::Id new_break_frame_id,
   thread_local_.frame_drop_mode_ = mode;
   thread_local_.break_frame_id_ = new_break_frame_id;
   thread_local_.restarter_frame_function_pointer_ =
-  // Temporary disabled for failing test investigation.
-  //    restarter_frame_function_pointer;
-      NULL;
+      restarter_frame_function_pointer;
 }