This recognizes escape paths that flow through informative definitions
as an escaping use. This only applies to HCheckMaps so far.

R=hpayer@chromium.org

Review URL: https://codereview.chromium.org/23514009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16420 ce2b1a6d-e550-0410-aec6-3dcde31c8c00