[PT2][Quant] Use module partition for fused patterns (#102394)
This diff introduces utility `find_sequential_partitions`.
This utility allows one to specify sequential pattern of
nn.Module/nn.functional and returns a list. Each item in the list contains a
List[SourcePartition] that represents sequentially connected partitions that
are of the pattern requested.
For example `find_sequential_partitions(model, [nn.Conv2d, nn.ReLU])` will find
all nn.Conv2d and nn.ReLU partitions that are sequentially connected.
Furthmore, move to using `find_sequential_partitions` for conv_bn/conv_bn_relu
for QAT.
Differential Revision: [D45948057](https://our.internmc.facebook.com/intern/diff/D45948057/)
**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D45948057/)!
Pull Request resolved: https://github.com/pytorch/pytorch/pull/102394
Approved by: https://github.com/jerryzh168
