[es6] Remove harmony-classes flag

test/mjsunit/harmony/classes-lazy-parsing.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 --min-preparse-length=0
-
-'use strict';
-
-class Base {
-  m() {
-    return 42;
-  }
-}
-
-class Derived extends Base {
-  m() {
-    return super.m();
-  }
-  evalM() {
-    return eval('super.m()');
-  }
-}
-
-assertEquals(42, new Derived().m());
-assertEquals(42, new Derived().evalM());
-
-
-class LazyDerived extends Base {
-  constructor() {
-    eval('super()');
-  }
-}
-assertInstanceof(new LazyDerived(), LazyDerived);
-assertInstanceof(new LazyDerived(), Base);