[Isolates] Merge from bleeding_edge, revisions 5934-6100.

test/mjsunit/regress/regress-3247124.js

 // Copyright 2010 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 32 matching lines @@
       if (a.substring(j, j + 1) == c) {
         c = b.substring(j, j + 1);
       }
     }
     r += c;
   }
 
   return r.toLowerCase();
 }
 
-for (var i = 0; i < 10000; i++) bar(foo);
+for (var i = 0; i < 100; i++) bar(foo);