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

[Shourya Goel via llvm-commits]

Sh0g0-1758 wrote:

and if it's not done yet, I suppose she can collaborate on this with me with the remaining work. I do think that the main goal when doing open-source contributions should be learning and collaboration and not focusing on just solving an issue. 

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