[llvm] [AMDGPU][GlobalISel] Align `selectVOP3PMadMixModsImpl` with the `SelectionDAG` counterpart (PR #110168)

[Jay Foad via llvm-commits]

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+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
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jayfoad wrote:

Is this test case `llvm-reduce`d already?

https://github.com/llvm/llvm-project/pull/110168