[turbofan] Optimize Int32Mod by power-of-two.

TEST=mjsunit/asm/int32-tmod,unittests
R=dcarney@chromium.org

Review URL: https://codereview.chromium.org/649083005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24554 ce2b1a6d-e550-0410-aec6-3dcde31c8c00