Unreviewed, skipping flaky test on GTK 64-bit debug bot.

        editing/selection/end-of-document.html is failing in the GTK 64-bit debug bot
        https://bugs.webkit.org/show_bug.cgi?id=53995

        * platform/gtk/Skipped: Skipped flaky test.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@78567 268f45cc-cd09-0410-ab3c-d52691b4dbfc