Intermittent crash in /_mozilla/webgl/conformance-1.0.3/conformance/more/glsl/uniformOutOfBounds.html

[nox]

Tests with unexpected results:
  ▶ ERROR [expected OK] /webgl/conformance-1.0.3/conformance/more/glsl/uniformOutOfBounds.html
  └   → Traceback (most recent call last):
  File "/Users/servo/buildbot/slave/mac-rel-wpt2/build/tests/wpt/harness/wptrunner/executors/base.py", line 149, in run_test
    result = self.do_test(test)
  File "/Users/servo/buildbot/slave/mac-rel-wpt2/build/tests/wpt/harness/wptrunner/executors/executorservo.py", line 133, in do_test
    self.proc.kill()
  File "/Users/servo/buildbot/slave/mac-rel-wpt2/build/python/_virtualenv/lib/python2.7/site-packages/mozprocess/processhandler.py", line 749, in kill
    self.proc.kill(sig=sig)
  File "/Users/servo/buildbot/slave/mac-rel-wpt2/build/python/_virtualenv/lib/python2.7/site-packages/mozprocess/processhandler.py", line 165, in kill
    send_sig(signal.SIGTERM)
  File "/Users/servo/buildbot/slave/mac-rel-wpt2/build/python/_virtualenv/lib/python2.7/site-packages/mozprocess/processhandler.py", line 152, in send_sig
    os.killpg(pid, sig)
OSError: [Errno 1] Operation not permitted

[nox]

Just tried it right now, it says:

 0:07.61 pid:37110 ERROR 2018-07-07T22:04:13Z: canvas::webgl_thread: Last GL operation failed: Uniform3fv(0, [0.0, 1.0, 2.0])
 0:07.61 pid:37110 assertion failed: `(left == right)`
 0:07.62 pid:37110   left: `1282`,
 0:07.62 pid:37110  right: `0`: Unexpected WebGL error: 0x502 (1282) (thread WebGLThread, at components/canvas/webgl_thread.rs:985)
 0:07.68 TEST_END: Test OK. Subtests passed 1/1. Unexpected 0

and then it succeeds, so we should probably keep it disabled for now.

[nox]

I fixed this when I implemented getUniform and fixed getUniformLocation, will reenable.

[jdm]

I have a PR open that reenables it.