Remove unnecessary coupling between Promise tests and Object.observe

test/promises-aplus/lib/global.js

 // Copyright 2014 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 16 matching lines @@
 
 var global = this.global || {};
 var setTimeout;
 var clearTimeout;
 
 (function() {
 var timers = {};
 var currentId = 0;
 
 function PostMicrotask(fn) {
-  var o = {};
-  Object.observe(o, function() {
-    fn();
-  });
-  // Change something to enqueue a microtask.
-  o.x = 'hello';
+  Promise.resolve().then(fn);
 }
 
 setInterval = function(fn, delay) {
   var i = 0;
   var id = currentId++;
   function loop() {
     if (!timers[id]) {
       return;
     }
     if (i++ >= delay) {
@@ skipping 14 matching lines @@
 
 setTimeout = function(fn, delay) {
   var id = setInterval(function() {
     fn();
     clearInterval(id);
   }, delay);
   return id;
 }
 
 }());