[clang] [Sema] Diagnose tautological bounds checks (PR #120222)

[Nikita Popov via cfe-commits]

nikic wrote:

@nathanchance You are correct, this warning should indeed respect `-fwrapv`/`-fno-strict-overflow`. Your patch looks reasonable to me as well.

https://github.com/llvm/llvm-project/pull/120222