Fixes return value of 'Date.now' (#2274)

'Date.now()' should return an integer value. Fixes #2272
JerryScript-DCO-1.0-Signed-off-by: Tibor Dusnoki tdusnoki@inf.u-szeged.hu

tests/jerry/regression-test-issue-2272.js

@@ -0,0 +1,25 @@
+// 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.
+
+Number.isInteger = Number.isInteger || function (value) {
+  return typeof value === 'number' &&
+    isFinite (value) &&
+    Math.floor (value) === value;
+};
+
+var now = Date.now ();
+
+assert (Number.isInteger (now));
+
+var date = new Date(now); // Should not throw an error