Remove Shadow DOM tests with high expectations.

These tests have been added by reading HTML spec,
where a:enabled and area:enabled are supposed to do something.
Unfortunately, in Blink they don't do anything (yet). We should
remove these tests, since they expect things we haven't yet
implemented (IOW, feature request, not a bug).

R=ojan@chromium.org, ojan
BUG=

Review URL: https://codereview.chromium.org/26319003

git-svn-id: svn://svn.chromium.org/blink/trunk@159050 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Rebaseline compositing image failures

None of these are perceptually different, so just rebaselining.

TBR=eseidel@chromium.org
BUG=

Review URL: https://codereview.chromium.org/26279006

git-svn-id: svn://svn.chromium.org/blink/trunk@159051 bbb929c8-8fbe-4397-9dbb-9b2b20218538