Move public symbols to the root set.

src/harmony-tostring.js

 // Copyright 2013 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.
 
 'use strict';
 
 // This file relies on the fact that the following declaration has been made
 // in runtime.js and symbol.js:
 // var $Object = global.Object;
 // var $Symbol = global.Symbol;
 
-var symbolToStringTag = InternalSymbol("Symbol.toStringTag");
-
 var kBuiltinStringTags = {
   "__proto__": null,
   "Arguments": true,
   "Array": true,
   "Boolean": true,
   "Date": true,
   "Error": true,
   "Function": true,
   "Number": true,
   "RegExp": true,
@@ skipping 41 matching lines @@
   // Set up the non-enumerable functions on the Array prototype object.
   var desc = ToPropertyDescriptor({
     value: ObjectToStringHarmony
   });
   DefineOwnProperty($Object.prototype, "toString", desc, false);
 
   %ToFastProperties($Object.prototype);
 }
 
 HarmonyToStringExtendObjectPrototype();