Refactor test_quantization.py and enable `test_nested` (#30475)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/30475
att
Test Plan:
python test/test_quantization.py
Imported from OSS
Differential Revision: D18795727
fbshipit-source-id: c9942c5361e0a34e91a08b8fc27405799db7ff4f
