[llvm] [DA] Add tests for nsw doesn't hold on entier iteration (PR #162281)

[Ryotaro Kasuga via llvm-commits]

kasuga-fj wrote:

Can you please move to a new PR/issue immediately? If you want to deepen your understanding, please do it over there. While it seems *you* have found something significant in this thread, I personally didn't find much that was new. Of course you are free to explore your ideas on your own, but I don't think this thread is the right place for it anymore.

I believe the original topic is a kind of issue related to API design (e.g., maybe we should define something like `isMonotonicAt` and `isMonotonicOnEntireIteration` separately). This is completely different from what you are discussing now.

https://github.com/llvm/llvm-project/pull/162281