if the right hand side is a literal like true, false, etc.
Also if the value is not a likely Smi we inline the newspace
check.
Review URL: http://codereview.chromium.org/2833048

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4999 ce2b1a6d-e550-0410-aec6-3dcde31c8c00