[llvm] [lit] Remove python3 version check (NFC) (PR #105948)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 approved this pull request.

LGTM.

Is there a reason you're only touching this version check? A cursory search seems to show ~30 files that are still checking for Python versions that are now below the LLVM minimum requirements.

https://github.com/llvm/llvm-project/pull/105948