Rebaseline a scroll parent layout test for linux

TBR=johnme@chromium.org
BUG=395103
NOTRY=true

Review URL: https://codereview.chromium.org/400983002

git-svn-id: svn://svn.chromium.org/blink/trunk@178437 bbb929c8-8fbe-4397-9dbb-9b2b20218538