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

[Michael Kruse via llvm-commits]

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Meinersbur wrote:

@amehsan Even if (there is some discussion about allocation larger than half the virtual address space in because `ptrdiff_t` would overflow, but this a limitation for the programming language C, not LLVM-IR, see https://lists.llvm.org/pipermail/llvm-dev/2017-November/118901.html), there are machines with 128 bit addresses as well. The loop variable could also be 32 bits, and so far we haven't even talked about force-promoting all variables to match the virtual address space.

[except](https://discourse.llvm.org/t/rfc-a-new-pass-as-an-alternative-to-dependenceanalysis/88403/4)

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