[llvm] [LoopVectorize] Add test case for minloc reduction (PR #141556)

[Madhur Amilkanthwar via llvm-commits]

madhur13490 wrote:

Regardless of what we agree on https://github.com/llvm/llvm-project/pull/144987, I think the test is still useful to have. Ping to @fhahn, @Mel-Chen 

https://github.com/llvm/llvm-project/pull/141556