The build hasn't worked for months (even on 20.09). Now also my
dedicated machine broke, and I don't feel like maintaining it until
the job has any chance of succeeding.
(I don't know why exactly it's failing.)
These have a hug log that will hit “log limit exceeded” on Hydra. This
commit skips the biggest offenders - qaDrv and qaDrvAggresive, giving
smaller logs.
https://hydra.nixos.org/build/94487387
From these three values, I believe it's most meaningful to track
one of the higher ones and their difference (qaCountBroken).
It's a bit unclear which of the higher ones - I have no data on that,
so I kept the one used before the parent commit.
Before ae16dd1a15 `nix-env.qaCount` and
`nix-env.qaCountDrv` were equivalent, after that change that is no longer
the case so this needs a separate metric now.
