[quan][fusion] Fix a additional_fuser_method method for fuse_fx (#67876)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67876
Previously we miss it when we call obj.convert and this argument would not impact the fusion.
This PR fixes it and adds a test for it
Test Plan:
python test/test_quantization.py TestFuseFx
Imported from OSS
Reviewed By: malfet
Differential Revision: D32191364
fbshipit-source-id: 566bd39461010d70a21de71f611bb929976fe01d
