- `spack.cmd.all_commands` does a directory listing on `lib/spack/spack/cmd`, regardless of whether it is needed - make this lazy so that the directory listing won't happen unless it's necessary.
- `spack.cmd.all_commands` does a directory listing on `lib/spack/spack/cmd`, regardless of whether it is needed - make this lazy so that the directory listing won't happen unless it's necessary.