[llvm] [SelectionDAG] Add more cases for UDIV and SDIV (PR #86452)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon requested changes to this pull request.

Please branch off the KnownBits.cpp changes into its own PR

Also, still waiting for test cases :) 

https://github.com/llvm/llvm-project/pull/86452