xla

e9a1c5f9 - Remove OpenXLA CUDA fallback and `_XLAC_cuda_functions.so` extension. (#9581)

Remove OpenXLA CUDA fallback and `_XLAC_cuda_functions.so` extension. (#9581) This PR removes the OpenXLA CUDA fallback implementation, and also the `_XLA_cuda_functions.so` extension, completely. Starting on this PR, the fallback shall be run only on CPU. **Key Changes:** - Remove _aten_cuda_functions.cpp_ and _aten_cuda_functions.h_ - Remove the OpenXLA CUDA fallback functions from _aten_fallback.cpp_ - Remove the `_XLAC_cuda_functions.so` library from _BUILD_ - Remove the Python `_XLAC_cuda_functions.so` extension from _setup.py_ - Remove the conditional loading of `_XLAC_cuda_functions.so` Python extension from _torch_xla/__init__.py_