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

[Ryotaro Kasuga via llvm-commits]

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kasuga-fj wrote:

No, SCEV can infer nowrap flags without IR's `nsw`, for example by constant range analysis. You can see `nsw`s are inferred by running `'print<scalar-evolution>`.

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