[llvm] [DA] remove constraint propagation and coupled/separable subscripts (PR #160924)

[Ryotaro Kasuga via llvm-commits]

https://github.com/kasuga-fj commented:

This patch does at least the following three things:

- Removing constraint propagation
- Removing `getSplitIteration`
- Disabling `banerjeeMIV` by default

Can you please separate out these changes into separate PRs? I think the easiest first step is to remove `getSplitIteration`.

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