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

[Paul Kirth via llvm-commits]

https://github.com/ilovepi approved this pull request.

LGTM, but let’s modify the commit message slightly. First, it’s not really important to include the context about the “not —crash” bits. Additionally, the precise error code isn’t important only that the command failed. 

This patch is really about the internal shell’s support for printing the environment as output. So let’s trim it down to just those bits. 

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