[llvm] Upstreaming warning suppression to LLVM (PR #83590)

[Aaron Ballman via llvm-commits]

AaronBallman wrote:

> Has this been reported to the MLIR project? Should they be fixing the warning, or have they made some affirmative decision to use or avoid std::complex of integers? They even have `std::complex<APInt>`, which is exciting.

Even if MLIR is intentionally using these, I don't think the correct fix is to disable the warning project-wide; they can disable the warning locally easily enough with a `#define`.

https://github.com/llvm/llvm-project/pull/83590