Fix remainder type promotion (#48668)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/48668
Combine tests for `fmod` and `remainder`.
## BC-breaking Note:
In order to make `remainder` operator have type promotion, we have to introduce BC breaking.
### 1.7.1:
In the case where the second argument is a python number, the result is casted to the dtype of the first argument.
```python
>>> torch.remainder(x, 1.2)
tensor([0, 0, 0, 0, 0], dtype=torch.int32)
```
### This PR:
In the case where the second argument is a python number, the dtype of result is determined by type promotion of both inputs.
```python
>>> torch.remainder(x, 1.2)
tensor([1.0000, 0.8000, 0.6000, 0.4000, 0.2000])
```
Test Plan: Imported from OSS
Reviewed By: mruberry
Differential Revision: D25869136
Pulled By: ejguan
fbshipit-source-id: 8e5e87eec605a15060f715952de140f25644008c
