[llvm] [llvm-mca] Add optional identifier field to mca::Instruction (PR #97867)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

Adding an identifier seems like it might not be a bad option given the current design. If it helps multiple downstream consumers, then it seems reasonable enough to me. We don't need any of this sort of functionality in our downstream usage (so far), but I can see how it would potentially be useful for others.

I'll defer to the primary `llvm-mca` reviewers here as I'm not really qualified to review changes like this in this area of the project.

https://github.com/llvm/llvm-project/pull/97867