Fix return value of PyErr_WarnEx ignored (SystemError) (#44371)
Summary:
This PR fixes unexpected `SystemError` when warnings are emitted and warning filters are set.
## Current behavior
```
$ python -Werror
>>> import torch
>>> torch.range(1, 3)
UserWarning: torch.range is deprecated in favor of torch.arange and will be removed in 0.5. Note that arange generates values in [start; end), not [start; end].
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
SystemError: <built-in method range of type object at 0x7f38c7703a60> returned a result with an error set
```
## Expected behavior
```
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
UserWarning: torch.range is deprecated and will be removed in a future release because its behavior is inconsistent with Python's range builtin. Instead, use torch.arange, which produces values in [start, end).
```
## Note
Python exception must be raised if `PyErr_WarnEx` returns `-1` ([python docs](https://docs.python.org/3/c-api/exceptions.html#issuing-warnings)). This PR fixes warnings raised in the following code:
```py
import torch
torch.range(1, 3)
torch.autograd.Variable().volatile
torch.autograd.Variable().volatile = True
torch.tensor(torch.tensor([]))
torch.tensor([]).new_tensor(torch.tensor([]))
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/44371
Reviewed By: mrshenli
Differential Revision: D23598410
Pulled By: albanD
fbshipit-source-id: 2fbcb13fe4025dbebaf1fd837d4c8e0944e05010
