[llvm] [CI] Disable Flang from pre-commit tests when Flang files are not touched on Windows Only (PR #93729)

[Valentin Clement バレンタイン クレメン via llvm-commits]

clementval wrote:

Thanks Mehdi! That would be a nice solution to keep what seems to be stable and disable what is not. 

https://github.com/llvm/llvm-project/pull/93729