Port torch.copysign method_tests() to OpInfo (#54945)
Summary:
Related https://github.com/pytorch/pytorch/issues/54261
This PR ports the method_tests() entries of `torch.copysign` to OpInfo.
While porting the tests, the `test_out` cases from `test_ops.py` would fail as the out variant of `torch.copysign` does not support scalar inputs.
```python
>>> x = torch.randn(2)
>>> y = torch.empty_like(x)
>>> torch.copysign(x, 1.)
tensor([1.4836, 1.2156])
>>> torch.copysign(x, 1., out=y)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: copysign(): argument 'other' (position 2) must be Tensor, not float
```
This PR fixes the tests by adding an overload `native_functions` entry and re-dispatching scalar inputs to the existing `copysign_out` function.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/54945
Reviewed By: gchanan
Differential Revision: D27505300
Pulled By: mruberry
fbshipit-source-id: f68250fa52f8dcfd45426039ec178ca5e883e206
