[dynamo] implement custom dict variable as a general solution for HF's ModelOutput class (#105044)
before the PR, for HF's ModelOutput class, we use dicts.py/DataClassVariable with our own implementation on __getItem__, __setAttr__, __setItem__. There is a risk that ModelOutput logic may change since it is a user code
after the PR, we inline __getItem__, __setAttr__, __setItem__ using dicts.py/CustomizedDictVariable so the logic always keep AA
unit test
* python test/dynamo/test_model_output.py -k test_HF_bert_model_output
test on HF benchmark
* python benchmarks/dynamo/huggingface.py -d cuda --inference --accuracy --progress --inductor --print-dataframe-summary 2>&1
* all metric are the same before/after the PR, including pass rate, unique_graphs, graph_breaks, unique_graph_breaks
* before the PR: P790393916
* after the PR: P790368991
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105044
Approved by: https://github.com/jansel
