[llvm] [IVUsers] Make IV-use collection independent of SSA use-list order (PR #215261)

[via llvm-commits]

elle-j wrote:

For the tests, all check lines were generated with the patched binaries: `update_llc_test_checks.py` for the CodeGen tests, `update_test_checks.py` for the Transforms tests (including the new one).

https://github.com/llvm/llvm-project/pull/215261