[llvm] [lit] Are all RUN lines skipped in windows cmd? (PR #65242)

[James Henderson via llvm-commits]

jh7370 wrote:

What is `%dbg` actually used for? I couldn't find any references to it in the main LLVM tests, nor is there any reference to it in the Testing Guid docs, so I suspect I'm missing something crucial to understanding this situation...

> I would like to understand whether windows `cmd` as a lit external shell is worthwhile to support anymore.

We probably should, purely on the basis that people who develop on Windows might be using this setup. That being said, I'm fairly confident that Windows users by default use the internal shell. I have not verified that though.

https://github.com/llvm/llvm-project/pull/65242