[llvm] [LoopInterchange] Bail out for Scalar Dependencies (PR #119345)

[Ryotaro Kasuga via llvm-commits]

kasuga-fj wrote:

I agree with removing the 'S'. I think leaving the incorrect dependencies risks causing correctness issues, especially when we change the code in the future.  At the extreme, we need to insert something like `if (Direction == 'S') { ... }` as this patch does when adding new functions.

https://github.com/llvm/llvm-project/pull/119345