[bootstrapper] Remove Intl experimental natives files

src/js/string.js

 // Copyright 2012 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.
 
 (function(global, utils) {
 
 %CheckIsBootstrapping();
 
 // -------------------------------------------------------------------
 // Imports
@@ skipping 88 matching lines @@
     }
   }
 
   if (end_i <= start_i) {
     return '';
   }
 
   return %_SubString(s, start_i, end_i);
 }
 
+// TODO(littledan): Rewrite these four functions as C++ builtins
 // ECMA-262, 15.5.4.16
 function StringToLowerCaseJS() {
   CHECK_OBJECT_COERCIBLE(this, "String.prototype.toLowerCase");
 
   return %StringToLowerCase(TO_STRING(this));
 }
 
 
 // ECMA-262, 15.5.4.17
 function StringToLocaleLowerCase() {
@@ skipping 219 matching lines @@
   "bold", StringBold,
   "fixed", StringFixed,
   "italics", StringItalics,
   "small", StringSmall,
   "strike", StringStrike,
   "sub", StringSub,
   "sup", StringSup
 ]);
 
 })