these 2 derivations will be built:
  /nix/store/rj2h3a7pk8viya88q3srqix4fm5p4c87-nixos-test-driver-pg_repack.drv
  /nix/store/a1qq3azlqdf3y295ynhhn4gqaps4xz15-vm-test-run-pg_repack.drv