[llvm] [DAG] Add legalization handling for ABDS/ABDU (PR #92576)

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

Thanks @nathanchance - I've confirmed thats addressed by my fix for the report from @ZequanWu - I'm going to push the fixed patch shortly. 

https://github.com/llvm/llvm-project/pull/92576