Get rid of deprecated methods accessing mutator_thread_ instead of current thread

runtime/vm/isolate.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/isolate.h"
 
 #include "include/dart_api.h"
 #include "include/dart_native_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
@@ skipping 1632 matching lines @@
 
     ISOLATE_METRIC_LIST(ISOLATE_METRIC_PRINT);
 #undef ISOLATE_METRIC_PRINT
     THR_Print("\n");
   }
 }
 
 
 void Isolate::Shutdown() {
   ASSERT(this == Isolate::Current());
-  ASSERT(top_resource() == NULL);
 #if defined(DEBUG)
   if (heap_ != NULL) {
     // The VM isolate keeps all objects marked.
     heap_->Verify(this == Dart::vm_isolate() ? kRequireMarked : kForbidMarked);
   }
 #endif  // DEBUG
 
   // Wait until all background compilation has finished.
   BackgroundCompiler::Stop(background_compiler_);
 
@@ skipping 938 matching lines @@
                            serialized_message_, serialized_message_len_);
 }
 
 
 void IsolateSpawnState::Cleanup() {
   SwitchIsolateScope switch_scope(I);
   Dart::ShutdownIsolate();
 }
 
 }  // namespace dart