Implement this binding for arrow functions.

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

tests/jerry/es2015/arrow-this.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.
+ */
+
+var o = {
+  x: 13,
+
+  f: function()
+  {
+    return () => this.x + 1
+  },
+
+  g: function()
+  {
+    return function() {
+      return this.x + 1
+    }
+  }
+}
+
+assert(o.f().call(o) === 14);
+assert(o.g().call(o) === 14);
+
+assert(o.f()() === 14);
+
+var o2 = { x:4, f:o.f(), g:o.g() }
+
+assert(o2.f() === 14);
+assert(o2.g() === 5);