This change improves the ConstructStub and the ArgumentsAccessStub slightly
by using the cmov instruction (if available) to eliminate a 
conditional branch. It only applies to the IA-32 and X64 platforms.


Review URL: http://codereview.chromium.org/519035

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@3537 ce2b1a6d-e550-0410-aec6-3dcde31c8c00