[es6] Remove harmony-classes flag

test/mjsunit/harmony/class-computed-property-names-super.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-computed-property-names --harmony-sloppy
-// Flags: --harmony-classes --allow-natives-syntax
+// Flags: --allow-natives-syntax
 
 
 function ID(x) {
   return x;
 }
 
 
 (function TestComputedMethodSuper() {
   class Base {
     m() {
@@ skipping 50 matching lines @@
   }
   new Derived().a = 2;
   assertEquals('a 2', value);
   new Derived().b = 3;
   assertEquals('b 3', value);
   new Derived()[0] = 4;
   assertEquals('0 4', value);
   new Derived()[1] = 5;
   assertEquals('1 5', value);
 })();