[llvm] Remark Util introduce remark count (PR #66214)

[Florian Hahn via llvm-commits]

https://github.com/fhahn requested changes to this pull request.

Just noticed there are some build failures: https://buildkite.com/llvm-project/github-pull-requests/builds/6840#018b196d-9977-4b10-abf6-002c37b825ae

`std::variant` is only available in c++17, but LLVM defaults to c++14, so it cannot be used.

https://github.com/llvm/llvm-project/pull/66214