Update test expectations for fast/scrolling/scrollbar-tickmarks-hittest.html after r155279.

BUG=267206
TBR=morrita@chromium.org

Review URL: https://codereview.chromium.org/21671002

git-svn-id: svn://svn.chromium.org/blink/trunk@155369 bbb929c8-8fbe-4397-9dbb-9b2b20218538