Layout Test fast/js/JSON-stringify.html is failing

Test started failing on Mac Release consitently after Blink
r159506 landed.

TBR=tkent
NOTRY=true
BUG=306929

Review URL: https://codereview.chromium.org/27150002

git-svn-id: svn://svn.chromium.org/blink/trunk@159560 bbb929c8-8fbe-4397-9dbb-9b2b20218538