[promise] make Promise.resolve match spec

src/js/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.
 
 (function(global, utils, extrasUtils) {
 
 "use strict";
 
 %CheckIsBootstrapping();
 
@@ skipping 299 matching lines @@
 }
 
 function PromiseCatch(onReject) {
   return this.then(UNDEFINED, onReject);
 }
 
 // Combinators.
 
 function PromiseCast(x) {
   if (!IS_RECEIVER(this)) {
-    throw MakeTypeError(kCalledOnNonObject, PromiseCast);
+    throw MakeTypeError(kCalledOnNonObject, "Promise.resolve");
   }
-  if (IsPromise(x) && x.constructor === this) {
-    return x;
-  } else {
-    return new this(function(resolve, reject) { resolve(x) });
-  }
+  if (IsPromise(x) && x.constructor === this) return x;
+
+  var promiseCapability = NewPromiseCapability(this);
+  var resolveResult = %_Call(promiseCapability.resolve, UNDEFINED, x);
+  return promiseCapability.promise;
 }
 
 function PromiseAll(iterable) {
   var deferred = NewPromiseCapability(this);
   var resolutions = [];
   try {
     var count = 0;
     var i = 0;
     for (var value of iterable) {
       var reject = function(r) { deferred.reject(r) };
@@ skipping 106 matching lines @@
 [PromiseChain, PromiseDeferred, PromiseResolved].forEach(
     fn => %FunctionRemovePrototype(fn));
 
 utils.Export(function(to) {
   to.PromiseChain = PromiseChain;
   to.PromiseDeferred = PromiseDeferred;
   to.PromiseResolved = PromiseResolved;
 });
 
 })