Back out "[ONNX] Process const folding progressively when converts to ONNX (#54569)"
Summary: Original commit changeset: 833dac7c71f2
Test Plan:
```
buck test mode/dev //pytext/fb/assistant/lite/test:test -- --exact
'pytext/fb/assistant/lite/test:test - test_export_bytes_model_to_caffe2
(pytext.fb.assistant.lite.test.test.TestExport)'
```
Reviewed By: jeanm
Differential Revision: D28431840
fbshipit-source-id: 0f1d530034404421a5d51691173e1cc0ee16fdd6
