[llvm] [SCEV] - Set PositiveStride when adding stride > 0 predicate. (PR #228015)

[Pawan Nirpal via llvm-commits]

pawan-nirpal-031 wrote:

@fhahn can you review, Apologies I now see why this should have been done in the parent PR, I thought there might be more to it than just setting PositiveStride to True. 

https://github.com/llvm/llvm-project/pull/228015