Port `slow_conv_transpose2d` to structured (#55503)
Summary: Pull Request resolved: https://github.com/pytorch/pytorch/pull/55503
Test Plan: Imported from OSS
Reviewed By: ejguan
Differential Revision: D29945028
Pulled By: SplitInfinity
fbshipit-source-id: 0b696d104938287444210f1bc926afc13f899991
