[MPS] Fix cumsum for integral data types (#94530)
- Make intermediate type for cumsum ScalarType::Int: fixes https://github.com/pytorch/pytorch/issues/90635
- Add support for negative dimensions in cumsum: fixes https://github.com/pytorch/pytorch/issues/92329
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94530
Approved by: https://github.com/kulinseth
