[llvm] [IR] Do not track metadata uses of ConstantData (PR #223303)

[Stephen Tozer via llvm-commits]

SLTozer wrote:

> My only worry is whether there's something in the metadata loader that make use of replaceability of ConstantData during deserialisation; CC @SLTozer, any reason for concern there?

I believe not - any `ConstantData` that may be used by VAM should not be forward referenced, and since they don't have a use list anyway it wouldn't work if you tried to RAUW them.

https://github.com/llvm/llvm-project/pull/223303