deps: V8: cherry-pick 6c1b7a313b81

Signed-off-by: ulofiai <monsterking@tutamail.com>

Author: ulofiai

deps/v8/src/handles/persistent-handles.cc

@@ -124,6 +124,9 @@ void PersistentHandlesList::Remove(PersistentHandles* persistent_handles) {
 
 void PersistentHandlesList::Iterate(RootVisitor* visitor, Isolate* isolate) {
   isolate->heap()->safepoint()->AssertActive();
+  // Use the lock here because PersistentHandles could be dropped from threads
+  // without a LocalHeap.
+  base::MutexGuard guard(&persistent_handles_mutex_);
   for (PersistentHandles* current = persistent_handles_head_; current;
        current = current->next_) {
     current->Iterate(visitor);