Revert "Use constant types to represent the fixed right arg of a MOD."

This reverts commit r18246 for tanking all benchmarks.

TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/104243002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18249 ce2b1a6d-e550-0410-aec6-3dcde31c8c00