[Dynamo] Fix several bugs & code refactor in RangeVariable (#89322)
Fix bug in [7k github models](https://github.com/pytorch/torchdynamo/issues/1884): https://github.com/jansel/pytorch-jit-paritybench/blob/master/generated/test_clovaai_stargan_v2.py
```
E TypeError: 'list' object cannot be interpreted as an integer
E
E from user code:
E File "/scratch/ybliang/work/repos/pytorch-jit-paritybench/generated/test_clovaai_stargan_v2.py", line 335, in forward
E idx = torch.LongTensor(range(y.size(0)))
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/89322
Approved by: https://github.com/jansel