these 2 derivations will be built:
  /nix/store/57xmx1a67ki09aprws8l227b5rss4qm8-nixos-test-driver-pg_repack.drv
  /nix/store/psm2nbdpvlfzhjq8hp34zrr8amqsjj63-vm-test-run-pg_repack.drv