[llvm] [LoopInterchange] Drop nuw/nsw flags from reduction ops when interchanging (PR #148612)

[Ryotaro Kasuga via llvm-commits]

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

> It would be better to drop the nuw/nsw flags during the transform instead.
> 
> (Generally speaking, adding flags should never regress optimization.)

Thanks, changed in such a way.

https://github.com/llvm/llvm-project/pull/148612