Merged r16303 into trunk branch.

Fix mjsunit/debug-script after r16298

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/22843006

git-svn-id: https://v8.googlecode.com/svn/trunk@16304 ce2b1a6d-e550-0410-aec6-3dcde31c8c00