[google/4_7] Patch committed: backport the static prediction for short-circuit patch from trunk

[Dehao Chen]

I have backported r192215 from trunk to google-4_7:

        2012-10-08  Dehao Chen  <de...@google.com>

        * predict.c (predict_extra_loop_exits): Use
        predict_paths_leading_to_edge to replace predict_edge_def.

Bootstrapped and passed crosstool test.

Dehao