Implement computed properties for object literals. (#2481)

Also disable ES5.1 property name dumplication checks
when ES2015 object literals are enabled.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

tests/jerry/es5.1/object-literal-fails.js

@@ -0,0 +1,47 @@
+// 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.
+
+function throw_error(snippet)
+{
+  try
+  {
+    eval(snippet);
+    assert (false);
+  }
+  catch (e)
+  {
+    assert (e instanceof SyntaxError);
+  }
+}
+
+function throw_error_strict(snippet)
+{
+  'use strict'
+
+  try
+  {
+    eval(snippet);
+    assert (false);
+  }
+  catch (e)
+  {
+    assert (e instanceof SyntaxError);
+  }
+}
+
+// These should be failed in ECMA-262 v5.1
+throw_error_strict("({a:1, a:2})");
+throw_error("({a:1, get a() { return 1 }})");
+throw_error("({get a() {return undefined}, get a() {return undefined}})");
+throw_error("({ get 1() {}, 1:1 })");