Mark mediasource-duration.html as flaky crash

Mark mediasource-duration.html as flaky crash

At least on windows dbg and linux dbg, mediasource-duration.html has
started crashing since I landed the removal of short-circuiting
redundant seeks to same time in Chromium yesterday
(https://crrev.com/a609797f).

BUG=527152
TBR=philipj@opera.com
TEST=http/tests/media/media-source/mediasource-duration.html

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201574

[wolenetz, 2015-09-01 19:40:21]

I landed https://codereview.chromium.org/1325823005 before noticing this test is
now flakily crashing a DCHECK in chromium dbg builds. I'll investigate on the
Chromium side, but mark this flaky crashing for now. Sorry for the recent churn
on these, though the underlying fixes in Chromium for bug 526337 were sorely
needed.

I'll send to CQ shortly.

[wolenetz, 2015-09-01 19:40:28]

The CQ bit was checked by wolenetz@chromium.org

[commit-bot: I haz the power, 2015-09-01 19:40:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1308063006/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1308063006/1

[commit-bot: I haz the power, 2015-09-01 21:56:19]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201574