[MPS] Add testcase for copying cpu tensors into strided mps tensors (#91784)
Fixes https://github.com/pytorch/pytorch/issues/86975
If the destination is a strided MPS tensor and the source is a CPU tensor, we cannot perform a blit directly to copy the memory from the CPU tensor into the MPS tensor. We need to scatter the data into the right indices.
```
a1 = torch.Tensor([[1,2],[3,4], [5,6]]).to(torch.device("mps"))
b1 = torch.Tensor([-1, -1])
a1[1:,1] = b1 # strided MPS destination / contiguous CPU source
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/91784
Approved by: https://github.com/kulinseth
