[llvm] [ProfCheck][NFC] Make Function argument from branch weight setter optional (PR #166032)

[Aiden Grossman via llvm-commits]

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

LGTM.

Would be good to have Florian and/or Nikita take a look at this as well thouh.

https://github.com/llvm/llvm-project/pull/166032