Report the apptest fixture name for isolated fixture crashes.

Report the apptest fixture name for isolated fixture crashes.

Report specific Suite.Fixture crashes instead of mojo:foo_apptest.
Better than reporting 'mojo:foo_apptests' for each of 10 fixtures, eg.:
http://build.chromium.org/p/chromium.mojo/builders/Chromium%20Mojo%20Windows/builds/58/steps/app_tests/logs/stdio

TODO: Similar reporting (and avoid crashing fixtures) when not isolated.

BUG=509880
TEST=Better logging for apptest crashes on isolated fixtures.
R=sky@chromium.org

Committed: https://crrev.com/d28ff1ecf96d0650a60283be1b73df31d8e9ff65
Cr-Commit-Position: refs/heads/master@{#342228}

[msw, 2015-08-06 19:24:54]

Hey Scott, please take a look; thanks!

[sky, 2015-08-06 20:03:08]

LGTM

[msw, 2015-08-06 20:13:06]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2015-08-06 20:13:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1275123002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1275123002/1

[commit-bot: I haz the power, 2015-08-06 21:08:40]

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

[commit-bot: I haz the power, 2015-08-06 21:08:41]

Try jobs failed on following builders:
  win_chromium_x64_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_x64_...)

[msw, 2015-08-06 21:50:09]

The CQ bit was checked by msw@chromium.org

[commit-bot: I haz the power, 2015-08-06 21:50:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1275123002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1275123002/1

[commit-bot: I haz the power, 2015-08-06 23:20:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-06 23:20:50]

Patchset 1 (id:??) landed as
https://crrev.com/d28ff1ecf96d0650a60283be1b73df31d8e9ff65
Cr-Commit-Position: refs/heads/master@{#342228}