[quant] Enable reduce_range for graphmode (#39874)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/39874
When fbgemm backend is set we make sure reduce_range is set to true to avoid overflow in the operator
Also adds test for per-channel quant with graph mode and compare numerics with eager mode
Test Plan:
python test/test_quantization.py
Imported from OSS
Differential Revision: D22011205
fbshipit-source-id: 1c7c9b7ab0d84200e3d8d85c34978554c30c0169
