Change the order of arguments of the (One|Two)ByteSeqStringSetChar intrinsic.

test/mjsunit/regress/regress-seqstrsetchar-ex1.js

 // Copyright 2013 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 29 matching lines @@
   var i;
   for (i = 0; i < n; i++) {
     var code = %_Arguments(i);
     if (!%_IsSmi(code)) code = ToNumber(code) & 0xffff;
     if (code > 0xff) break;
   }
 
   var two_byte = %NewString(n - i, false);
   for (var j = 0; i < n; i++, j++) {
     var code = %_Arguments(i);
-    %_TwoByteSeqStringSetChar(two_byte, j, code);
+    %_TwoByteSeqStringSetChar(j, code, two_byte);
   }
   return one_byte + two_byte;
 }
 
 StringFromCharCode(0xFFF, 0xFFF);
 StringFromCharCode(0x7C, 0x7C);
 %OptimizeFunctionOnNextCall(StringFromCharCode);
 StringFromCharCode(0x7C, 0x7C);
 StringFromCharCode(0xFFF, 0xFFF);