[pytorch][papaya] Replace parseObject with dummy function in FlatBufferLoader during load parameters (#79167)
Summary: As titled.
Test Plan:
```
buck test //xplat/caffe2:test_lite_trainer_pickle_and_flatbuffer //xplat/caffe2:test_lite_trainer
```
Differential Revision: D37021858
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79167
Approved by: https://github.com/qihqi
