Do not crash when switch threads while debugging.

src/debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
 #include "code-stubs.h"
@@ skipping 493 matching lines @@
   thread_local_.step_count_ = 0;
   thread_local_.last_fp_ = 0;
   thread_local_.queued_step_count_ = 0;
   thread_local_.step_into_fp_ = 0;
   thread_local_.step_out_fp_ = 0;
   thread_local_.after_break_target_ = 0;
   // TODO(isolates): frames_are_dropped_?
   thread_local_.debugger_entry_ = NULL;
   thread_local_.has_pending_interrupt_ = false;
   thread_local_.restarter_frame_function_pointer_ = NULL;
+
+  promise_catch_handlers_.Clear();
+  promise_getters_.Clear();
 }
 
 
 char* Debug::ArchiveDebug(char* storage) {
   char* to = storage;
   OS::MemCopy(to, reinterpret_cast<char*>(&thread_local_), sizeof(ThreadLocal));
   ThreadInit();
   return storage + ArchiveSpacePerThread();
 }
 
@@ skipping 3020 matching lines @@
   logger_->DebugEvent("Put", message.text());
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   LockGuard<Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 } }  // namespace v8::internal