[promise] make Promise.resolve match spec

src/js/promise.js

Index: src/js/promise.js
diff --git a/src/js/promise.js b/src/js/promise.js
index a165817b7160ec3798f34e01917f5f4a8467a27b..6fc8728562c03f4e5def5bc4d3dcc72088b90b75 100644
--- a/src/js/promise.js
+++ b/src/js/promise.js
@@ -317,13 +317,13 @@ function PromiseCatch(onReject) {
 
 function PromiseCast(x) {
   if (!IS_RECEIVER(this)) {
-    throw MakeTypeError(kCalledOnNonObject, PromiseCast);
-  }
-  if (IsPromise(x) && x.constructor === this) {
-    return x;
-  } else {
-    return new this(function(resolve, reject) { resolve(x) });
+    throw MakeTypeError(kCalledOnNonObject, "Promise.resolve");
   }
+  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) {