Fix fast/js/JSON-stringify.html expectations in response to V8 roll.

BUG=
TBR=acolwell@chromium.org

Review URL: https://codereview.chromium.org/174233002

git-svn-id: svn://svn.chromium.org/blink/trunk@167529 bbb929c8-8fbe-4397-9dbb-9b2b20218538