Fix OOB write in --print-code.

R=jkummerow@chromium.org
BUG=v8:2624

Review URL: https://chromiumcodereview.appspot.com/14018010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14267 ce2b1a6d-e550-0410-aec6-3dcde31c8c00