Break typecheck dependency in escape analysis.

R=mstarzinger@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22803002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16146 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Make assert more accurate

BUG=
R=verwaest@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22623008

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

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16147 ce2b1a6d-e550-0410-aec6-3dcde31c8c00