Unreviewed GTK gardening. Adding expectations for the current test failures.
Adding a GTK-specific baseline for a recently introduced a11y test.

* platform/gtk/TestExpectations:
* platform/gtk/accessibility/press-targets-center-point-expected.txt: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@160283 268f45cc-cd09-0410-ab3c-d52691b4dbfc