Move microtask queueing logic from JavaScript to C++

src/promise.js

 // 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.
 
 "use strict";
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js:
 // var $Object = global.Object
 // var $WeakMap = global.WeakMap
@@ skipping 133 matching lines @@
       break;
   }
   return deferred.promise;
 }
 
 function PromiseCatch(onReject) {
   return this.then(UNDEFINED, onReject);
 }
 
 function PromiseEnqueue(value, tasks) {
-  EnqueueMicrotask(function() {
+  %EnqueueMicrotask(function() {
     for (var i = 0; i < tasks.length; i += 2) {
       PromiseHandle(value, tasks[i], tasks[i + 1])
     }
   });
 }
 
 function PromiseHandle(value, handler, deferred) {
   try {
     %DebugPromiseHandlePrologue(
         function() {
@@ skipping 138 matching lines @@
 SetUpPromise();
 
 // Functions to expose promise details to the debugger.
 function GetPromiseStatus(promise) {
   return GET_PRIVATE(promise, promiseStatus);
 }
 
 function GetPromiseValue(promise) {
   return GET_PRIVATE(promise, promiseValue);
 }