[es6] Remove harmony-classes flag

test/mjsunit/harmony/classes-maps.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-classes --allow-natives-syntax
-'use strict';
-
-(function TestMaps() {
-  class Base {}
-  class Derived extends Base {}
-
-  let d1 = new Derived();
-  let d2 = new Derived();
-
-  assertTrue(%HaveSameMap(d1, d2));
-}());
-
-
-(function TestProtoModificationArray() {
-  let called = 0;
-  function F() {
-    called++;
-    assertFalse(Array.isArray(this));
-  }
-  class Derived extends Array {}
-  assertSame(Derived.__proto__, Array);
-
-  let d1 = new Derived();
-  assertTrue(Array.isArray(d1));
-
-  Derived.__proto__ = F;
-  called = 0;
-  let d2 = new Derived();
-  assertSame(1, called);
-  assertFalse(Array.isArray(d2));
-
-  assertFalse(%HaveSameMap(d1, d2));
-}());
-
-
-(function TestProtoModification() {
-  let called = 0;
-  function F() {
-    called++;
-    let exn = null;
-    try {
-      this.byteLength;
-    } catch (e) {
-      exn = e;
-    }
-    assertTrue(exn instanceof TypeError);
-  }
-  class Derived extends Uint8Array {
-    constructor() { super(10); }
-  }
-  assertSame(Derived.__proto__, Uint8Array);
-
-  let d1 = new Derived();
-  assertSame(10, d1.byteLength);
-
-  Derived.__proto__ = F;
-  called = 0;
-  let d2 = new Derived();
-  assertSame(1, called);
-  assertThrows(function() { d2.byteLength; }, TypeError);
-
-  assertFalse(%HaveSameMap(d1, d2));
-}());