Implement ES2015 class feature (part II.) (#2439)

This patch is the second milestone of the implementation of this new language element.

Supported:
 - Single class inheritance
 - Functionality of 'super' keyword
 - Implicit constructor in class heritage
 - Specific behaviour while extending with the built-in 'Array' or '%TypedArray%' object
 - Abstract subclasses (Mix-ins)

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

tests/jerry/es2015/class-inheritance-core-1.js

@@ -0,0 +1,116 @@
+/* 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.
+ */
+
+class Animal {
+  constructor (name) {
+    this.name = name;
+  }
+
+  hello () {
+    return "Hello I am " + this.name;
+  }
+
+  static speak () {
+    return "Animals roar.";
+  }
+
+  static explain () {
+    return "I can walk,";
+  }
+
+  whoAmI () {
+    return "I am an Animal.";
+  }
+
+  breath () {
+    return "I am breathing.";
+  }
+
+  get myName () {
+    return this.name;
+  }
+
+  set rename (name) {
+    this.name = name;
+  }
+}
+
+class Dog extends Animal {
+  constructor (name, barks) {
+    super (name);
+    this.barks = barks;
+  }
+
+  hello () {
+    return super.hello () + " and I can " + (this.barks ? "bark" : "not bark");
+  }
+
+  whoAmI () {
+    return "I am a Dog.";
+  }
+
+  static speak () {
+    return "Dogs bark.";
+  }
+
+  static explain () {
+    return super.explain () + " jump,";
+  }
+
+  bark () {
+    return this.barks ? "Woof" : "----";
+  }
+}
+
+class Doge extends Dog {
+  constructor (name, barks, awesomeness) {
+    super (name, barks);
+    this.awesomeness = awesomeness;
+  }
+
+  hello () {
+    return super.hello () + " and I'm " + (this.awesomeness > 9000 ? "super awesome" : "awesome") + ".";
+  }
+
+  whoAmI ( ) {
+    return "I am a Doge.";
+  }
+
+  static speak () {
+    return "Doges wow.";
+  }
+
+  static explain () {
+    return super.explain () + " dance.";
+  }
+}
+
+var doge = new Doge ("doggoe", true, 10000);
+assert (doge.name === "doggoe");
+doge.rename = "doggo";
+assert (doge.myName === "doggo");
+assert (doge.barks === true);
+assert (doge.awesomeness === 10000);
+assert (doge.hello () === "Hello I am doggo and I can bark and I'm super awesome.");
+assert (doge.whoAmI () === "I am a Doge.");
+assert (doge.breath () === "I am breathing.");
+assert (doge.bark () === "Woof");
+assert (Doge.speak () === "Doges wow.");
+assert (Doge.explain () === "I can walk, jump, dance.");
+assert (doge instanceof Animal);
+assert (doge instanceof Dog);
+assert (doge instanceof Doge);
+assert (Dog.prototype.constructor === Dog)
+assert (Doge.prototype.constructor === Doge)