Fixed power-of-2 predicates, excluding 0.

R=dslomov@chromium.org

Review URL: https://codereview.chromium.org/219213003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20383 ce2b1a6d-e550-0410-aec6-3dcde31c8c00