Remove JSON-stringify layout test.

This test will be moved to the V8 repo.

R=jochen@chromium.org, ulan@chromium.org
TBR=jochen@chromium.org
BUG=367089

Review URL: https://codereview.chromium.org/255813004

git-svn-id: svn://svn.chromium.org/blink/trunk@172627 bbb929c8-8fbe-4397-9dbb-9b2b20218538