Reviewed by Adam Roben.

        media/audio-delete-while-slider-thumb-clicked.html failing on Windows since r78562
        https://bugs.webkit.org/show_bug.cgi?id=54502

        * media/audio-delete-while-slider-thumb-clicked.html: Avoid deleting the element twice.
        * platform/win/Skipped: unskip the test.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@78701 268f45cc-cd09-0410-ab3c-d52691b4dbfc