xla

647804ca - Remove remaining GPU/CUDA mentions in `torch_xla` directory. (#9608)

Remove remaining GPU/CUDA mentions in `torch_xla` directory. (#9608) This PR removes the remaining CUDA specific code from the PyTorch/XLA package (i.e. `torch_xla` directory) as well a few other related files. This is in line with the CUDA deprecation that started on release 2.8. **Key Changes:** - (`CONTRIBUTING.md`) Removed mention to CUDA specific environment variables - (`configuration.yaml`) Removed description of CUDA specific environment variables - (`docs/source/learn/_pjrt.md`) Removed PjRt documentation on CUDA - (`torch_xla/amp`) Removed CUDA specific branches, as well as `GradScaler` - (`torch_xla/core/xla_env_vars.py`) Removed CUDA specific environment variables - (`torch_xla/utils/checkpoint.py`) Fixed incorrect function name