Drive-By-Fix: Improve ARM code generation for flooring division by
power of 2.

BUG=v8:3204
LOG=y
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/196653009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19877 ce2b1a6d-e550-0410-aec6-3dcde31c8c00