[rfc] list tests known to fail on a platform

[Alexander Belchenko]

Mark Hammond пишет:
> If a bug number was associated with and printed for each of the tests that
> were supressed it might help keep things on the radar.  One or 2 tests
> already do that - eg:
> 
> blackbox.test_info.TestInfo.test_info_locking     XFAIL
> 553ms
>     OS locks are exclusive for different processes (Bug #174055)
> 
> Which interestingly enough looks like the exact same issue causing the
> LockContention failures.

This test xfailed because bzr info code is wrong re showing WT lock
and there is bug number so anybody could see what's actually wrong.
It's not directly related to common problem with locks.