[2/2] Intel GPU Runtime Upstreaming for Generator (#118613)
# Motivation
According to [[1/2] Intel GPU Runtime Upstreaming for Generator](https://github.com/pytorch/pytorch/pull/118528), as mentioned in [[RFC] Intel GPU Runtime Upstreaming](https://github.com/pytorch/pytorch/issues/114842), the second PR covers the changes under `python frontend`.
# Design
Currently, it primarily offers geneartor-related APIs, including
- `torch.xpu.default_generators`
- `torch.xpu.get_rng_state`
- `torch.xpu.get_rng_state_all`
- `torch.xpu.initial_seed`
- `torch.xpu.manual_seed`
- `torch.xpu.manual_seed_all`
- `torch.xpu.seed`
- `torch.xpu.seed_all`
- `torch.xpu.set_rng_state`
- `torch.xpu.set_rng_state_all`
# Additional Context
The differences with CUDA:
The generator-related frontend python APIs are 1:1 mapping with CUDA.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/118613
Approved by: https://github.com/gujinghui, https://github.com/EikanWang, https://github.com/jgong5, https://github.com/albanD
