[clang] [clang][python] Make .git_archival.txt deterministic. (PR #223362)

[Cristian Le via cfe-commits]

LecrisUT wrote:

Sure thing. It is a bit weird to me because that should only display either the tag or maybe the git deacribe which would combine the latest git tag, distance and hash, which should be impossible to collide. @akuegel can you provide more details and example file (fine if mocked) to how this would fail?

https://github.com/llvm/llvm-project/pull/223362