Revert "Rebaseline virtual/threaded/compositing/visibility/visibility-image-layers.html"

The Chromium CL that caused these rebaselines has been reverted.

Review URL: https://codereview.chromium.org/399753002

git-svn-id: svn://svn.chromium.org/blink/trunk@178297 bbb929c8-8fbe-4397-9dbb-9b2b20218538