x64 BinaryOpStub uses wrong registers in one code path

R=yangguo@chromium.org,svenpanne@chromium.org
x64 BinaryOpStub::GenerateSmiCode use wrong registers in one code path.

e.g. d8 --trace_ic
var dd = new Float64Array(2);
dd[1] = 1;
(function fn() {
  for (var i = 0; i < 1000; i++)
  dd[0] = 2 / dd[1];
})();
It keeps falling into runtime call and patching.

No regression test, because I don't how to test it.

Committed: https://code.google.com/p/v8/source/detail?r=12226

[Zheng Liu, 2012-07-30 11:50:41]

PTAL

[Yang, 2012-07-30 13:03:39]

On 2012/07/30 11:50:41, Zheng Liu wrote:
> PTAL

LGTM. There indeed doesn't seem to be any simple way to create a regression test
for this. I'm landing the patch.