Implement Object.{entries, values} built-in methods (#3993)

Object.keys also updated to follow the ES11 standard.

JerryScript-DCO-1.0-Signed-off-by: Roland Takacs rtakacs@inf.u-szeged.hu

tests/jerry/es.next/object-keys.js

@@ -0,0 +1,46 @@
+// 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.
+
+var object = {};
+
+Object.defineProperties(object, {
+  a: {
+    value: "foo",
+    enumerable: false
+  },
+  b: {
+    value: "bar",
+    enumerable: true,
+    writable: false
+  }
+});
+
+var proxy = new Proxy(object, {
+  getOwnPropertyDescriptor: function(o, v) {
+    handlers.push("D");
+    return Object.getOwnPropertyDescriptor(o, v);
+  },
+  get: function(o, v) {
+    handlers.push("G");
+    return o[v];
+  }
+});
+
+var handlers = [];
+var keys = Object.keys(proxy);
+
+assert(keys.length === 1);
+assert(keys[0] === "b");
+assert(handlers.length === 2);
+assert(handlers.toString() === "D,D");