Allow HChange instructions to be hoisted out of loops. To avoid
unnecessary code motion we don't hoist instructions from blocks that
have been marked containing an unconditional deoptimization.
Review URL: http://codereview.chromium.org/7003087

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8245 ce2b1a6d-e550-0410-aec6-3dcde31c8c00