There's no reason to check if we've failed when (a) we know we have
and (b) we've got a perfectly good NULL just lying around anyway.

Review URL: http://codereview.chromium.org/155920

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2522 ce2b1a6d-e550-0410-aec6-3dcde31c8c00