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

[Ehsan Amiri via llvm-commits]

amehsan wrote:

> (1) I wonder if there is a proof of correctness of these tests in the literature that we can look into and figure out what are the assumptions for each one?

This book may have the proofs
[Dependence Analysis
 by Utpal Banerjee](https://play.google.com/store/info/name/Utpal_Banerjee?id=050zr_2)


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