Fix problem with GenericBinaryOperationStub::GenerateCall for a Smi...

Fix problem with GenericBinaryOperationStub::GenerateCall for a Smi
left operand.  For non-commutative operations the right operand could
be overwritten with the Smi left operand.

We need better testing of all of these cases.  We will add more test
cases as a separate commit.

Committed: http://code.google.com/p/v8/source/detail?r=3834

[Mads Ager (chromium), 2010-02-11 11:41:09]

Please double check this carefully.  We need to generate regression test cases
for this.

[Kevin Millikin (Chromium), 2010-02-11 12:05:57]

LGTM.