these 2 derivations will be built:
  /nix/store/0wq0hxxbvyn0k307l38s9k1nca4kfgal-nixos-test-driver-pg_repack.drv
  /nix/store/yyb4wynmykkdzifw7cy0wx1m4f9xm504-vm-test-run-pg_repack.drv