[quant][pt2] Add Conv + BN + ReLU fusion for prepare QAT (#100283)
Summary: This follows https://github.com/pytorch/pytorch/pull/98568,
which lays all the groundwork for Conv + BN fusion in prepare QAT.
Conv + BN + ReLU fusion can reuse the same match and replace
patterns and is handled similarly.
Test Plan:
python test/test_quantization.py TestQuantizePT2E.test_prepare_qat_conv_bn_relu_fusion
python test/test_quantization.py TestQuantizePT2E.test_prepare_qat_conv_bn_relu_numerics
Reviewers: kimishpatel, jerryzh168
Differential Revision: [](https://our.internmc.facebook.com/intern/diff/)
Differential Revision: [D45515494](https://our.internmc.facebook.com/intern/diff/D45515494)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/100283
Approved by: https://github.com/jerryzh168
