Classes: Add test for method prototype

test/mjsunit/harmony/classes.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --harmony
 
 (function TestBasics() {
   var C = class C {}
   assertEquals(typeof C, 'function');
   assertEquals(C.__proto__, Function.prototype);
@@ skipping 154 matching lines @@
   assertEquals('class E { x() { 42; } }', E.toString());
 })();
 
 
 function assertMethodDescriptor(object, name) {
   var descr = Object.getOwnPropertyDescriptor(object, name);
   assertTrue(descr.configurable);
   assertTrue(descr.enumerable);
   assertTrue(descr.writable);
   assertEquals('function', typeof descr.value);
+  assertFalse('prototype' in descr.value);
 }
 
 function assertGetterDescriptor(object, name) {
   var descr = Object.getOwnPropertyDescriptor(object, name);
   assertTrue(descr.configurable);
   assertTrue(descr.enumerable);
   assertEquals('function', typeof descr.get);
   assertEquals(undefined, descr.set);
 }
 
@@ skipping 207 matching lines @@
   class C {
     constructor() {
       assertThrows(function() {
         C = 42;
       }, ReferenceError);
     }
   }
   new C();
 })();
 */