fractional_max_pool2d_backward: port to structured kernel (#68245)
Summary:
Ported to structured kernel the fractional_max_pool2d_backward.
Ref https://github.com/pytorch/pytorch/issues/55070
Pull Request resolved: https://github.com/pytorch/pytorch/pull/68245
Reviewed By: jbschlosser
Differential Revision: D33405521
Pulled By: bdhirsh
fbshipit-source-id: 4930e870d4025485317208df751bc3721ecdb7eb
