standalone/TestRunnerTest fails sporadically with timeout on all platforms

[whesse]

On buildbot, TestRunnerTest fails with one of its 4 processes not terminating, occasionally. Disabled for now, in standalone.status.

[whesse]

Added Accepted label.

[madsager]

I believe I have a fix for this. I'm reenabling the test. Let's keep an eye on it.

---

cc @whesse.
Set owner to @madsager.
Removed Area-Library label.
Added Area-VM label.

[madsager]

Added Fixed label.