Remove CUDA specific path from internal Python packages. (#9606)
This PR removes CUDA specific code from internal Python packages, such
as `_dynamo`, files in `_internal`, and the main `__init__.py` file.
This is in line with the CUDA deprecation that started on release 2.8.
**Key Changes:**
- (`torch_xla/__init__.py`) Removed GPU specific OpenXLA flag
- (`torch_xla/_dynamo/dynamo_bridge.py`) Removed CUDA tensor movement
- As far as I know, mainly created for the zero overhead CUDA tensor
movement
