Use compiled model in torch.compiler_get_started (#107267)
- Text says `Next, let’s try a real model like resnet50 from the PyTorch` but the code example uses `resnet18`. Fixed code to use `resnet50` for consistency.
- One of the examples in TorchDynamo Overview uses uncompiled model - fixed it - now it uses compiled model.
- Removed unused import to `_dynamo` in one of the examples
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107267
Approved by: https://github.com/soulitzer
