[llvm] [mlir] [ADT] Add implementations for mulhs and mulhu to APInt (PR #84609)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

@Sh0g0-1758 I thought the conclusion of the discussion of #84207 was that @Atousa was working on this?

https://github.com/llvm/llvm-project/pull/84609