[llvm] [LV] Add support for absolute difference partial reductions (PR #188043)

[Benjamin Maxwell via llvm-commits]

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+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
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MacDue wrote:

Removed these tests (the PRs can land it any order)

https://github.com/llvm/llvm-project/pull/188043