Merged r17422 into trunk branch.

Function ElementsAreSafeToExamine was undefined in release heap verify.

R=jkummerow@chromium.org
BUG=

Review URL: https://codereview.chromium.org/50103004

git-svn-id: https://v8.googlecode.com/svn/trunk@17423 ce2b1a6d-e550-0410-aec6-3dcde31c8c00