Add remaining @@toStringTag symbols to builtins

src/json.js

 // Copyright 2009 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 declarations have been made
 // in runtime.js:
 // var $Array = global.Array;
 // var $String = global.String;
@@ skipping 202 matching lines @@
   }
   return JSONSerialize('', {'': value}, replacer, new InternalArray(), "", gap);
 }
 
 
 // -------------------------------------------------------------------
 
 function SetUpJSON() {
   %CheckIsBootstrapping();
 
+  %AddNamedProperty($JSON, symbolToStringTag, "JSON", READ_ONLY | DONT_ENUM);
+
   // Set up non-enumerable properties of the JSON object.
   InstallFunctions($JSON, DONT_ENUM, $Array(
     "parse", JSONParse,
     "stringify", JSONStringify
   ));
 }
 
 SetUpJSON();
 
 
 // -------------------------------------------------------------------
 // JSON Builtins
 
 function JSONSerializeAdapter(key, object) {
   var holder = {};
   holder[key] = object;
   // No need to pass the actual holder since there is no replacer function.
   return JSONSerialize(key, holder, UNDEFINED, new InternalArray(), "", "");
 }