[reland][quant] Add backward compatiblity test (#36842)
Summary:
re-created the same PR: https://github.com/pytorch/pytorch/pull/36639
because ghimport does not support importing binary files right now
Pull Request resolved: https://github.com/pytorch/pytorch/pull/36842
Test Plan: python test/quantization/test_backward_compatibility.py
Differential Revision: D21100689
Pulled By: jerryzh168
fbshipit-source-id: 625a0f9da98138c9c2891b9d99fc45d85fa27cca
