add graph dumping utilities (#82184)
### Description
Add compiler function to dump the forward, backward, and joint graphs. The partitioner is default partition.
The input meta to each dumped graphs will also be dumped as a pickle file.
Example usage:
```
save_fx_func = graph_dumper_aot(current_name, folder_name, dump_example_input = False)
optimize_ctx = torchdynamo.optimize(
save_fx_func
)
with torch.enable_grad():
with optimize_ctx:
result = forward_and_backward_pass(model, example_inputs)
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/82184
Approved by: https://github.com/Chillee
