[llvm] [ObjC][ProvenanceEval] Only evaluate pointers (PR #136876)

[Florian Hahn via llvm-commits]

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

LGTM, but probably good to wait a day or so in case @ahatanak or @rjmccall have additional thoughts

https://github.com/llvm/llvm-project/pull/136876