[llvm] [mlir] Add llvm::min/max_element and use it in llvm/ and mlir/ directories. (PR #84678)

[Mehdi Amini via llvm-commits]

https://github.com/joker-eph approved this pull request.

I wish the standard librairies would provide these shortcuts!

https://github.com/llvm/llvm-project/pull/84678