[Mac Lion] media/W3C/video/events/event_canplay.html is flakey, sometimes times out
https://bugs.webkit.org/show_bug.cgi?id=114889

* platform/mac-lion/TestExpectations:
Mark it as such.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148773 268f45cc-cd09-0410-ab3c-d52691b4dbfc