Merged r16406, r16431 into 3.19 branch.

Delete HAbnormalExit. It does more harm than good.

Always visit branches during HGraph building

BUG=v8:2843,chromium:280333
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/23548009

git-svn-id: https://v8.googlecode.com/svn/branches/3.19@16486 ce2b1a6d-e550-0410-aec6-3dcde31c8c00