Completely remove InterruptableThreadState and Fix ThreadRegistry leak

runtime/vm/isolate.h

 // 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.
 
 #ifndef VM_ISOLATE_H_
 #define VM_ISOLATE_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 616 matching lines @@
   void set_profiler_data(IsolateProfilerData* profiler_data) {
     profiler_data_ = profiler_data;
   }
 
   IsolateProfilerData* profiler_data() const {
     return profiler_data_;
   }
 
   void PrintJSON(JSONStream* stream, bool ref = true);
 
-  InterruptableThreadState* thread_state() const {
-    return (mutator_thread_ == NULL) ? NULL : mutator_thread_->thread_state();
-  }
-
   CompilerStats* compiler_stats() {
     return compiler_stats_;
   }
 
   // Returns the number of sampled threads.
   intptr_t ProfileInterrupt();
 
   VMTagCounters* vm_tag_counters() {
     return &vm_tag_counters_;
   }
@@ skipping 259 matching lines @@
   static Dart_FileWriteCallback file_write_callback_;
   static Dart_FileCloseCallback file_close_callback_;
   static Dart_EntropySource entropy_source_callback_;
   static Dart_IsolateInterruptCallback vmstats_callback_;
 
   static void WakePauseEventHandler(Dart_Isolate isolate);
 
   // Manage list of existing isolates.
   static void AddIsolateTolist(Isolate* isolate);
   static void RemoveIsolateFromList(Isolate* isolate);
-  static void CheckForDuplicateThreadState(InterruptableThreadState* state);
 
   static Monitor* isolates_list_monitor_;  // Protects isolates_list_head_
   static Isolate* isolates_list_head_;
 
 #define REUSABLE_FRIEND_DECLARATION(name)                                      \
   friend class Reusable##name##HandleScope;
 REUSABLE_HANDLE_LIST(REUSABLE_FRIEND_DECLARATION)
 #undef REUSABLE_FRIEND_DECLARATION
 
   friend class GCMarker;  // VisitObjectPointers
@@ skipping 144 matching lines @@
   uint8_t* serialized_message_;
   intptr_t serialized_message_len_;
   Isolate::Flags isolate_flags_;
   bool paused_;
   bool errors_are_fatal_;
 };
 
 }  // namespace dart
 
 #endif  // VM_ISOLATE_H_