Avoid to run dart code during paused_on_exit

runtime/vm/message_handler.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_MESSAGE_HANDLER_H_
 #define RUNTIME_VM_MESSAGE_HANDLER_H_
 
 #include "vm/isolate.h"
 #include "vm/lockers.h"
 #include "vm/message.h"
@@ skipping 221 matching lines @@
   // This flag is not thread safe and can only reliably be accessed on a single
   // thread.
   bool oob_message_handling_allowed_;
   intptr_t live_ports_;  // The number of open ports, including control ports.
   intptr_t paused_;      // The number of pause messages received.
 #if !defined(PRODUCT)
   bool should_pause_on_start_;
   bool should_pause_on_exit_;
   bool is_paused_on_start_;
   bool is_paused_on_exit_;
+  MessageStatus paused_on_exit_status_;
   int64_t paused_timestamp_;
 #endif
   bool delete_me_;
   ThreadPool* pool_;
   ThreadPool::Task* task_;
   StartCallback start_callback_;
   EndCallback end_callback_;
   CallbackData callback_data_;
 
   DISALLOW_COPY_AND_ASSIGN(MessageHandler);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_MESSAGE_HANDLER_H_