[clang] [Clang] Implement P2864R2 Remove Deprecated Arithmetic Conversion on… (PR #73105)

[Piotr Zegar via cfe-commits]

PiotrZSL wrote:

Actually that is more like a quick fix, we can live with it. More proper way would be simply to split those tests into pre-c++20 and universal.

https://github.com/llvm/llvm-project/pull/73105