Export function symbols to enable Windows build of Intel Extension for PyTorch (#98054)
This PR is to export specific function symbols into .dll shared library on Windows platform to support Windows build for [Intel Extension for PyTorch](https://github.com/intel/intel-extension-for-pytorch).
TORCH_API/TORCH_PYTHON_API/PYBIND11_EXPORT are macros that decorate the function as dllexport while compilation, so that the function symbol will be exported into the .dll shared library file on Windows platform. It is necessary for other libraries (such as IPEX) to import and call these functions through dynamic linking of PyTorch on Windows platform.
The code changes of this PR adds decorators to export specific functions used by IPEX.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/98054
Approved by: https://github.com/ezyang
