Remove the scrollbar from fast/images/gray-scale-jpeg-with-color-profile

This test is just an image that happens to be larger than the viewport,
it doesn't need to test the pixel results of a scrollbar.

R=enne@chromium.org
BUG=364946

Review URL: https://codereview.chromium.org/248003002

git-svn-id: svn://svn.chromium.org/blink/trunk@172286 bbb929c8-8fbe-4397-9dbb-9b2b20218538