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

[James Henderson via llvm-commits]

https://github.com/jh7370 requested changes to this pull request.

This still hasn't been run through the python code formatter (and there's still trailing whitespace on the line I highlighted before).

See also https://llvm.org/docs/CodingStandards.html#python-version-and-source-code-formatting.

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