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

[Mel Chen via llvm-commits]

Mel-Chen wrote:

> Related PRs: #141431 and #141467.

No, I think this is https://github.com/llvm/llvm-project/pull/140451.
There is only one phi node involved the reduction.

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