Update TestExpectations for scroll-parent-absolute.

The scrollbars appear not to draw content by default in some configs, so
we need to have different text dumps.

TBR=senorblanco@chromium.org
BUG=None

Review URL: https://codereview.chromium.org/348613002

git-svn-id: svn://svn.chromium.org/blink/trunk@176542 bbb929c8-8fbe-4397-9dbb-9b2b20218538