Now we can correctly optimize top level code that contains a throw (or
return) as it's last statement.

R=ulan@chromium.org
BUG=v8:2054
TEST=mjsunit/regress/regress-2054

Review URL: https://chromiumcodereview.appspot.com/9969146

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11224 ce2b1a6d-e550-0410-aec6-3dcde31c8c00