insert_quant_dequant work with qconfig_dict (#25127)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/25127
Extend insert_quant_dequant pass to go through forward function graphs
Test Plan:
```
python test/test_jit.py 'TestJit.test_insert_quant_dequant'
python test/test_quantizer.py
```
Imported from OSS
Differential Revision: D17001137
fbshipit-source-id: 41b029906fe5c8bc0de01956059388a7d552a380
