Eliminated test flakiness for script-priorities

Eliminated test flakiness for script-priorities

The async scripts execute in non-deterministic order so I removed their
debug output.  The only thing we really care about testing in the
script-priorities layout test is the request priority which is
determined and logged deterministically at parse time (and still
captured).

BUG=413604
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=181919

[Pat Meenan, 2014-09-12 13:19:09]

pmeenan@chromium.org changed reviewers:
+ loislo@chromium.org

[Pat Meenan, 2014-09-12 13:19:10]

loislo@ PTAL (and sorry about the flaky test).

This still tests for what we need but eliminates the flakiness from async
scripts executing at arbitrary times.

Once the bots look green I'll submit a CL to revert the flaky expectation and
make it live again.

[loislo, 2014-09-12 13:23:13]

The CQ bit was checked by loislo@chromium.org

[loislo, 2014-09-12 13:23:13]

lgtm

[commit-bot: I haz the power, 2014-09-12 13:24:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/555463006/1

[commit-bot: I haz the power, 2014-09-12 15:12:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-09-12 15:12:43]

Try jobs failed on following builders:
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/26836)

[Pat Meenan, 2014-09-12 17:03:51]

The CQ bit was checked by pmeenan@chromium.org

[commit-bot: I haz the power, 2014-09-12 17:04:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/555463006/1

[commit-bot: I haz the power, 2014-09-12 17:56:22]

Committed patchset #1 (id:1) as 181919