Don't generate a shift left by one if can deoptimize on ia32 and arm and mips.

BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/21196006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15958 ce2b1a6d-e550-0410-aec6-3dcde31c8c00