Get rid of deprecated methods accessing mutator_thread_ instead of current thread

runtime/vm/timer.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 VM_TIMER_H_
 #define VM_TIMER_H_
 
 #include "platform/utils.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 90 matching lines @@
 // }
 class TimerScope : public StackResource {
  public:
   TimerScope(bool flag, Timer* timer, Thread* thread = NULL)
       : StackResource(thread),
         nested_(false),
         timer_(flag ? timer : NULL) {
     Init();
   }
 
-  TimerScope(bool flag, Timer* timer, Isolate* isolate = NULL)
-      : StackResource(isolate),
-        nested_(false),
-        timer_(flag ? timer : NULL) {
-    Init();
-  }
-
   void Init() {
     if (timer_ != NULL) {
       if (!timer_->running()) {
         timer_->Start();
       } else {
         nested_ = true;
       }
     }
   }
   ~TimerScope() {
@@ skipping 41 matching lines @@
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(PauseTimerScope);
 };
 
 
 
 }  // namespace dart
 
 #endif  // VM_TIMER_H_