When build using 'nix build' if we hit this default we will fail to
evaluate. Most instances that this should break have been fixed so
we remove this to prevent this from happening further in the future.
It's an ugly solution (like before), but some of us want to
nix-build nixos/tests/foo.nix
This PR makes that possible once more for tests are wired with `make-test-python.nix`.
When importing Nixpkgs within Nixpkgs, we should not consider aliases
to ensure we don't rely on them internally.
There are probably more places that need to be converted.
