Fix prepareElementsForSort crash bug=117879 . This is a back

src/regexp.js

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 329 matching lines @@
 
 function RegExpGetRightContext() {
   var start_index;
   var subject;
   if (!lastMatchInfoOverride) {
     start_index = lastMatchInfo[CAPTURE1];
     subject = LAST_SUBJECT(lastMatchInfo);
   } else {
     var override = lastMatchInfoOverride;
     subject = override[override.length - 1];
-    var pattern = override[override.length - 3];
-    start_index = override[override.length - 2] + pattern.length;
+    start_index = override[override.length - 2] + subject.length;
   }
   return SubString(subject, start_index, subject.length);
 }
 
 
 // The properties $1..$9 are the first nine capturing substrings of the last
 // successful match, or ''.  The function RegExpMakeCaptureGetter will be
 // called with indices from 1 to 9.
 function RegExpMakeCaptureGetter(n) {
   return function() {
@@ skipping 123 matching lines @@
   %DefineAccessor($RegExp, "$'", SETTER, NoOpSetter, DONT_ENUM | DONT_DELETE);
 
   for (var i = 1; i < 10; ++i) {
     %DefineAccessor($RegExp, '$' + i, GETTER, RegExpMakeCaptureGetter(i),
                     DONT_DELETE);
     %DefineAccessor($RegExp, '$' + i, SETTER, NoOpSetter, DONT_DELETE);
   }
 }
 
 SetUpRegExp();