Make js-test-post a noop.

Will delete the file in a followup patch.

Review URL: https://codereview.chromium.org/54473004

git-svn-id: svn://svn.chromium.org/blink/trunk@161115 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove V8 dependency from blink_platform

Review URL: https://codereview.chromium.org/54893003

git-svn-id: svn://svn.chromium.org/blink/trunk@161116 bbb929c8-8fbe-4397-9dbb-9b2b20218538