Fix invalid argument reference in Promise.all executor (#4885)

This patch fixes #4871.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik robert.fancsik@h-lab.eu

tests/jerry/es.next/regression-test-issue-4871.js

@@ -0,0 +1,40 @@
+// Copyright JS Foundation and other contributors, http://js.foundation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+resolved = false;
+
+function T(p, r, u) {
+  return Object.assign(p, {
+    then(onFulfilled, onRejected) {
+      if (u) {
+        onFulfilled(r);
+      } else {
+        onFulfilled();
+      }
+
+      return Promise.prototype.then.call(this, onFulfilled, onRejected);
+    }
+  });
+}
+
+var ps = [T(Promise.resolve('success'))];
+Promise.all(ps).then(res => {
+  resolved = true;
+}).catch(err => {
+  assert(false);
+});
+
+function __checkAsync() {
+  assert(resolved);
+}