[llvm] [profcheck] Require `unknown` metadata have an origin parameter (PR #157594)

[Aiden Grossman via llvm-commits]

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

Optimization remarks seems like good enough motivation to me.

I can't imagine the overhead of this is that high.

https://github.com/llvm/llvm-project/pull/157594