Fix WebGL 2.0 expectations and skip a test with an assertion failure.

Fix WebGL 2.0 expectations and skip a test with an assertion failure.

Query arguments weren't being stripped from file:// URLs by Python's
urlparse.urlsplit, which seems to have caused all WebGL 2.0
suppressions for specific pages to be ignored, instead taking any
wildcard suppressions for that platform or configuration. Fixed this
and added a unit test.

BUG=542901
TBR=zmo@chromium.org

Committed: https://crrev.com/f3e8c3fb1bf76ffb386034e3f6c8aee8e1bb3f07
Cr-Commit-Position: refs/heads/master@{#353933}

[Ken Russell (switch to Gerrit), 2015-10-14 00:01:28]

kbr@chromium.org changed reviewers:
+ zmo@chromium.org

[Ken Russell (switch to Gerrit), 2015-10-14 00:01:28]

All: I'm CQ'ing this TBR'd to fix the Windows Debug bots on the FYI waterfall.
It's likely that the bug with the query arg is also the reason the failure
suppressions for the Linux ATI bot weren't working.

[Ken Russell (switch to Gerrit), 2015-10-14 00:01:45]

The CQ bit was checked by kbr@chromium.org

[Ken Russell (switch to Gerrit), 2015-10-14 00:03:45]

+Ned as FYI. Slight chance that this query argument nastiness might affect other
parts of Telemetry.

[commit-bot: I haz the power, 2015-10-14 00:04:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1407643003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1407643003/1

[commit-bot: I haz the power, 2015-10-14 01:12:24]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-14 01:13:11]

Patchset 1 (id:??) landed as
https://crrev.com/f3e8c3fb1bf76ffb386034e3f6c8aee8e1bb3f07
Cr-Commit-Position: refs/heads/master@{#353933}