[llvm] [llvm-lit] Resolve env subcommand required error (PR #98414)

[Paul Kirth via llvm-commits]

https://github.com/ilovepi commented:

Thanks for adding the tests. I think this is pretty close for me, but I'm still a bit unsure about the early return. @petrhosek brought up a technical point about that, and I think we should determine if those are still a problem before landing this as is. If you can, provide some context on what you found, that may help us make that determination faster.

https://github.com/llvm/llvm-project/pull/98414