Restore expectation for fast/js/JSON-stringify.html dropped in r159254.

TBR=ojan@chromium.org
BUG=159254

Review URL: https://codereview.chromium.org/26584006

git-svn-id: svn://svn.chromium.org/blink/trunk@159261 bbb929c8-8fbe-4397-9dbb-9b2b20218538