Remove observer module after insert_quant_dequant (#28985)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/28985
Remove the observer module in the quantized model
Test Plan:
python test/test_jit.py 'TestJit.test_insert_quant_dequant'
Imported from OSS
Differential Revision: D18253777
fbshipit-source-id: 26081c4c3fd3dc049cafa8c0383219bc4c233589
