Delete video-durationchange-on-ended.html test

The changes which this test was added to verify have been
reverted because of issues in MSE playback. So this isn't
testing anything and is not useful.
So removing this test case.

Reverted change: http://crrev.com/1069253004

BUG=588956

Review-Url: https://codereview.chromium.org/2123083002
Cr-Commit-Position: refs/heads/master@{#403883}
2 files changed