[llvm] [DA] remove constraint propagation (PR #160924)

[Sebastian Pop via llvm-commits]

sebpop wrote:

> Consider removing [Constraint](https://github.com/llvm/llvm-project/blob/7bc3c24a4b7fb04186976366b8ba3e626512f75b/llvm/include/llvm/Analysis/DependenceAnalysis.h#L465-L548) class entirely.

Thanks for pointing this out!
As this is a larger rewrite, I will push it as a follow-up patch.

https://github.com/llvm/llvm-project/pull/160924