Reland r11425 "Re-enable optimization for hot functions that have optimization disabled due to many deopts."

Fix performance regressions introduced in r11425 by
- counting number of function deoptimizations instead of function optimizations,
- packing several counters into one field of shared function info.

BUG=v8:2040,121196
R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10534063

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11766 ce2b1a6d-e550-0410-aec6-3dcde31c8c00