Verify that source string matches serialized code.

R=mvstanton@chromium.org, vogelheim@chromium.org

Review URL: https://codereview.chromium.org/394793002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22417 ce2b1a6d-e550-0410-aec6-3dcde31c8c00