[llvm] [LIT][Cygwin] Skip pre-check for existence in mkdir-p (PR #163948)

[Alexander Richardson via llvm-commits]

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

Or maybe now that we depend on newer python we can just use the exist_ok=True parameter for mkdir? 

https://github.com/llvm/llvm-project/pull/163948