Prepare push to trunk.  Now working on version 3.22.10.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/26698003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17126 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Use the new introduced block's reachable flag.

BUG=
R=verwaest@chromium.org

Review URL: https://chromiumcodereview.appspot.com/26459002

Patch from Weiliang Lin <weiliang.lin2@gmail.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17129 ce2b1a6d-e550-0410-aec6-3dcde31c8c00