[llvm] [llvm-lit] Fix `TypeError` string argument expected in lit's internal shell (PR #105925)

[Paul Kirth via llvm-commits]

https://github.com/ilovepi commented:

This seems fine. IIRC there's a method to expand globs that may also be useful, but this seems straightforward enough of a conversion to just do it here.

My big question is why does this only need to be done for `args[-1]` and not the call to `stdio.write` above that uses `arg`? seems that they would have the same issue, right?

https://github.com/llvm/llvm-project/pull/105925