[Chromium] Test expectation update
https://bugs.webkit.org/show_bug.cgi?id=92941

* platform/chromium/TestExpectations:
accessibility/loading-iframe-updates-axtree.html is [ Timeout ].

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@142397 268f45cc-cd09-0410-ab3c-d52691b4dbfc