Add more instrumentation for Code::CopyFrom crasher.

R=jkummerow@chromium.org
BUG=chromium:196330

Review URL: https://codereview.chromium.org/12937004

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13991 ce2b1a6d-e550-0410-aec6-3dcde31c8c00