Allow new_full's fill_value argument type to be complex (#91345)
It seems that this code should type-check but doesn't:
```python
torch.zeros((2,3),dtype=torch.cdouble).new_full((4,5),complex(6,7))
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/91345
Approved by: https://github.com/zou3519, https://github.com/ezyang
