Top::external_caught_exception_ and Top::try_catch_handler_ are no
longer in sync.  Pulling it out until I have the time to fix it.
Review URL: http://codereview.chromium.org/42117

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1497 ce2b1a6d-e550-0410-aec6-3dcde31c8c00