[Mac] media/audio-repaint.html sometimes fails

[Jer Noble]

media/audio-repaint.html failed 10 out of 40 times on Lion Debug (Tests) between r114518 and r114644 (inclusive).

Failures:

http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114623%20(5680)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114621%20(5679)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114616%20(5677)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114594%20(5670)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114584%20(5668)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114569%20(5662)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114545%20(5654)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114541%20(5653)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114534%20(5651)/results.html
http://build.webkit.org/results/Lion%20Debug%20(Tests)/r114523%20(5649)/results.html

[Jer Noble]

AVFoundation appears to sometimes misreport the duration of the <audio> element's media.

[Andy Estes]

Committed r115891: <http://trac.webkit.org/changeset/115891>

[Ryosuke Niwa]

This test always fails now.