Fix split torch_function handling (#83866)
`Tensor.split` calls `TensorBase.split` whose `handle_torch_function` statement passes `func` as `Tensor.split` which is usually correct, but not here because of the use of `super()`. Instead this calls `torch._VF.split` which correctly differentiates from `torch.split`. This is currently okay since we never hit `TensorBase.split` for types with `__torch_function__` however, once we allow skipping only one hop of `__torch_function__` this will expose the error.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83866
Approved by: https://github.com/albanD
