[llvm] [SelectionDAG] Preserve poison for abs INT_MIN lowering (PR #183851)

[Simon Pilgrim via llvm-commits]

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

Please can you rewrite the patch title and description? Its still in terms of the original proposal and not ISD::ABS_MIN_POISON

https://github.com/llvm/llvm-project/pull/183851