[dynamo] support comparing stream with constant (#119199)
Before the pr, we have a graph break for:
```python
def f():
if torch.cuda.current_stream() is not None:
return torch.randn(2, 2)
torch.compile(f, backend="eager", fullgraph=True)()
```
This pr supports comparson ops of StreamVariable and ConstantVariable by returning a constant.
It's safe to return a constant in this case becuase the StreamVariable is guarded by ID_MATCH when created.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119199
Approved by: https://github.com/yifuwang, https://github.com/anijain2305, https://github.com/jansel
