Fixing retrieval of [[Class]] properties for built-in function objects, optimizing memory related to [[Class]] property.

- introduced ecma_object_get_class_name interface;
 - removed creation of [[Class]] internal property for types of objects that unambiguously determine the [[Class]] value.

Related issue: #112

JerryScript-DCO-1.0-Signed-off-by: Ruben Ayrapetyan r.ayrapetyan@samsung.com

tests/jerry/regression-test-issue-112.js

@@ -0,0 +1,16 @@
+// Copyright 2015 Samsung Electronics Co., Ltd.
+//
+// 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.
+
+delete Function.prototype.toString;
+assert (Math.cos + 1 === '[object Function]1');