Remove expectation for a test that was moved upstream in webkit r50900.
Remove expectation for a test that was moved upstream in webkit r50900.

  R=levin@chromium.org
  BUG=none
  TEST=LayoutTests/platform/mac-snowleopard/accessibility/aria-list-and-listitem.html

Review URL: http://codereview.chromium.org/393015

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@31937 0039d316-1c4b-4281-b951-d872f2087c98

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