Fix |RunMicrotasks()| leaking reference to the last context being run on.

src/contexts.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 160 matching lines @@
     call_as_constructor_delegate) \
   V(SCRIPT_FUNCTION_INDEX, JSFunction, script_function) \
   V(OPAQUE_REFERENCE_FUNCTION_INDEX, JSFunction, opaque_reference_function) \
   V(CONTEXT_EXTENSION_FUNCTION_INDEX, JSFunction, context_extension_function) \
   V(MAP_CACHE_INDEX, Object, map_cache) \
   V(EMBEDDER_DATA_INDEX, FixedArray, embedder_data) \
   V(ALLOW_CODE_GEN_FROM_STRINGS_INDEX, Object, allow_code_gen_from_strings) \
   V(ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX, Object, \
     error_message_for_code_gen_from_strings) \
   V(RUN_MICROTASKS_INDEX, JSFunction, run_microtasks) \
-  V(ENQUEUE_EXTERNAL_MICROTASK_INDEX, JSFunction, enqueue_external_microtask) \
+  V(ENQUEUE_MICROTASK_INDEX, JSFunction, enqueue_microtask) \
   V(IS_PROMISE_INDEX, JSFunction, is_promise) \
   V(PROMISE_CREATE_INDEX, JSFunction, promise_create) \
   V(PROMISE_RESOLVE_INDEX, JSFunction, promise_resolve) \
   V(PROMISE_REJECT_INDEX, JSFunction, promise_reject) \
   V(PROMISE_CHAIN_INDEX, JSFunction, promise_chain) \
   V(PROMISE_CATCH_INDEX, JSFunction, promise_catch) \
   V(TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX, JSFunction, \
     to_complete_property_descriptor) \
   V(DERIVED_HAS_TRAP_INDEX, JSFunction, derived_has_trap) \
   V(DERIVED_GET_TRAP_INDEX, JSFunction, derived_get_trap) \
@@ skipping 150 matching lines @@
     CALL_AS_FUNCTION_DELEGATE_INDEX,
     CALL_AS_CONSTRUCTOR_DELEGATE_INDEX,
     SCRIPT_FUNCTION_INDEX,
     OPAQUE_REFERENCE_FUNCTION_INDEX,
     CONTEXT_EXTENSION_FUNCTION_INDEX,
     OUT_OF_MEMORY_INDEX,
     EMBEDDER_DATA_INDEX,
     ALLOW_CODE_GEN_FROM_STRINGS_INDEX,
     ERROR_MESSAGE_FOR_CODE_GEN_FROM_STRINGS_INDEX,
     RUN_MICROTASKS_INDEX,
-    ENQUEUE_EXTERNAL_MICROTASK_INDEX,
+    ENQUEUE_MICROTASK_INDEX,
     IS_PROMISE_INDEX,
     PROMISE_CREATE_INDEX,
     PROMISE_RESOLVE_INDEX,
     PROMISE_REJECT_INDEX,
     PROMISE_CHAIN_INDEX,
     PROMISE_CATCH_INDEX,
     TO_COMPLETE_PROPERTY_DESCRIPTOR_INDEX,
     DERIVED_HAS_TRAP_INDEX,
     DERIVED_GET_TRAP_INDEX,
     DERIVED_SET_TRAP_INDEX,
@@ skipping 190 matching lines @@
   static bool IsBootstrappingOrGlobalObject(Isolate* isolate, Object* object);
 #endif
 
   STATIC_CHECK(kHeaderSize == Internals::kContextHeaderSize);
   STATIC_CHECK(EMBEDDER_DATA_INDEX == Internals::kContextEmbedderDataIndex);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CONTEXTS_H_