[promise] make Promise.resolve match spec

Fixes a number of test262 tests, including

- built-ins/Promise/resolve/resolve-from-promise-capability.js
- built-ins/Promise/resolve/context-non-object-with-promise.js
- built-ins/Promise/executor-function-length.js

BUG=v8:4633
LOG=N
R=littledan@chromium.org, cbruni@chromium.org

Review URL: https://codereview.chromium.org/1536013002

Cr-Commit-Position: refs/heads/master@{#33094}

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) {

test/mjsunit/es6/promises.js

@@ -47,6 +47,8 @@ function clear(o) {
   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])
   }
 }
@@ -1050,7 +1052,8 @@ function assertAsyncDone(iteration) {
 
   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() {

test/test262/test262.status

@@ -423,7 +423,6 @@
   'built-ins/Promise/all/same-reject-function': [FAIL],
 
   # https://bugs.chromium.org/p/v8/issues/detail?id=4633
-  'built-ins/Promise/resolve/resolve-from-promise-capability': [FAIL],
   'built-ins/Promise/resolve/capability-executor-not-callable': [FAIL],
   'built-ins/Promise/reject/capability-executor-not-callable': [FAIL],
   'built-ins/Promise/prototype/then/deferred-is-resolved-value': [SKIP],