Test TORCH_LIBRARY in CUDA extension (#47524)
Summary:
In the [official documentation](https://pytorch.org/tutorials/advanced/torch_script_custom_ops.html), it is recommended to use `TORCH_LIBRARY` to register ops for TorchScript. However, that code is never tested with CUDA extension and is actually broken (https://github.com/pytorch/pytorch/issues/47493). This PR adds a test for it. It will not pass CI now, but it will pass when the issue https://github.com/pytorch/pytorch/issues/47493 is fixed.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/47524
Reviewed By: zou3519
Differential Revision: D24991839
Pulled By: ezyang
fbshipit-source-id: 037196621c7ff9a6e7905efc1097ff97906a0b1c
