[promise] make Promise.resolve match spec

test/mjsunit/es6/promises.js

 // Copyright 2013 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 29 matching lines @@
   assertEquals("[object Promise]",
       Object.prototype.toString.call(new Promise(function() {})));
 })();
 
 
 function clear(o) {
   if (o === null || (typeof o !== 'object' && typeof o !== 'function')) return
   clear(o.__proto__)
   var properties = getOwnPropertyNames(o)
   for (var i in properties) {
+    // Do not clobber Object.prototype.toString, which is used by tests.
+    if (properties[i] === "toString") continue;
     clearProp(o, properties[i])
   }
 }
 
 function clearProp(o, name) {
   var poisoned = {caller: 0, callee: 0, arguments: 0}
   try {
     var x = o[name]
     o[name] = undefined
     clear(x)
@@ skipping 983 matching lines @@
   d6.resolve(6)
   assertTrue(log === "dncncnx6", "subclass/chain")
 
   log = ""
   Promise.all([11, Promise.accept(12), 13, MyPromise.accept(14), 15, 16])
 
   assertTrue(log === "nx14", "subclass/all/arg")
 
   log = ""
   MyPromise.all([21, Promise.accept(22), 23, MyPromise.accept(24), 25, 26])
-  assertTrue(log === "nx24nnx21nnnnx23nnnx25nnx26n", "subclass/all/self")
+  assertTrue(log === "nx24nnx21nnx[object Promise]nnx23nnnx25nnx26n",
+             "subclass/all/self")
 })();
 
 (function() {
   'use strict';
 
   class Pact extends Promise { }
   class Vow  extends Pact    { }
   class Oath extends Vow     { }
 
   Oath.constructor = Vow;
@@ skipping 41 matching lines @@
   var p = Promise.resolve();
   var callCount = 0;
   defineProperty(p, "constructor", {
     get: function() { ++callCount; return Promise; }
   });
   p.then();
   assertEquals(1, callCount);
 })();
 
 assertAsyncDone()