Use type info to allow ia32 to use the 32-bit versions in some cases.
Remove sse3-specific code from X64 GenericBinaryOpStub.

Review URL: http://codereview.chromium.org/1992011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4632 ce2b1a6d-e550-0410-aec6-3dcde31c8c00