Optimize fast element conversion in arm using batch store/loads.

test/mjsunit/elements-transition.js

 // Copyright 2011 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 65 matching lines @@
       }
     }
 
     assertEquals(length, array_1.length);
     assertEquals(length, array_2.length);
   }
 
   test(false, false, function(a,i,v){ a[i] = v; }, 20);
   test(true,  false, function(a,i,v){ a[i] = v; }, 20);
   test(false, true,  function(a,i,v){ a[i] = v; }, 20);
-  test(true,  true,  function(a,i,v){ a[i] = v; }, 10);
+  test(true,  true,  function(a,i,v){ a[i] = v; }, 20);
 
   test(false, false, function(a,i,v){ a[i] = v; }, 10000);
   test(true,  false, function(a,i,v){ a[i] = v; }, 10000);
   test(false, true,  function(a,i,v){ a[i] = v; }, 10000);
   test(true,  true,  function(a,i,v){ a[i] = v; }, 10000);
 } else {
   print("Test skipped because smi only arrays are not supported.");
 }