Hello!

So far our MariaDB package has only run some very lightweight tests.
10.1.34 flipped a switch that runs the entire "MTR" test suite.

After patching /bin/ls and /bin/sh, and fixing a couple of failures that
showed up after about 4 hours each, the most recent attempt took eight
hours during which my SSD was completely thrashed.  And then it failed a
test case related to the "disks" plugin.

The switch was flipped back shortly after the release:

https://github.com/MariaDB/server/commit/0a9d78f51d74be7708f2efd940311bf7b33108e9

Since 10.1.35 won't run these tests anymore, we could skip them for this
release and don't care about it.

Alternatively, we can replace the 'check' phase with something that
invokes "mtr" with sensible arguments, and passing our own list of tests
to skip.  That is what Debian does:

https://salsa.debian.org/mariadb-team/mariadb-10.1/blob/stretch/debian/rules#L96

Thoughts?

I'm leaning towards the latter approach, since I've already spent
considerable time tracking down related failures, and it already
identified a potential problem in the "disks" plugin.  But it means
building MariaDB will take many hours even on powerful machines.