[clang] [llvm] Reapply "[llvm][IR] Extend BranchWeightMetadata to track provenance o… (PR #95281)

[Paul Kirth via llvm-commits]

ilovepi wrote:

@nikic can you confirm the latest version doesn't regress anything? I tested locally, and with the missing line, the text section is unchanged from the previous commit.

https://github.com/llvm/llvm-project/pull/95281