Remove legacy restart code

runtime/vm/thread.h

 // Copyright (c) 2015, 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_THREAD_H_
 #define RUNTIME_VM_THREAD_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/atomic.h"
@@ skipping 488 matching lines @@
     return OFFSET_OF(Thread, active_stacktrace_);
   }
 
   uword resume_pc() const { return resume_pc_; }
   void set_resume_pc(uword value) { resume_pc_ = value; }
   static uword resume_pc_offset() { return OFFSET_OF(Thread, resume_pc_); }
 
   RawError* sticky_error() const;
   void set_sticky_error(const Error& value);
   void clear_sticky_error();
+  RawError* get_and_clear_sticky_error();
 
   RawStackTrace* async_stack_trace() const;
   void set_async_stack_trace(const StackTrace& stack_trace);
   void set_raw_async_stack_trace(RawStackTrace* raw_stack_trace);
   void clear_async_stack_trace();
   static intptr_t async_stack_trace_offset() {
     return OFFSET_OF(Thread, async_stack_trace_);
   }
 
   CompilerStats* compiler_stats() { return compiler_stats_; }
@@ skipping 297 matching lines @@
 // Disable thread interrupts.
 class DisableThreadInterruptsScope : public StackResource {
  public:
   explicit DisableThreadInterruptsScope(Thread* thread);
   ~DisableThreadInterruptsScope();
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_THREAD_H_