Fix strided _conv_double_backward() with 3D input / weight (#67283)
Summary:
Removes the 3D special case logic in `_convolution_double_backward()` that never worked.
The logic was never called previously since `convolution()` expands input / weight from 3D -> 4D before passing them to backends; backend-specific backward calls thus save the 4D version to pass to `_convolution_double_backward()`.
The new general `convolution_backward()` saves the original 3D input / weight, uncovering the bug.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67283
Reviewed By: anjali411
Differential Revision: D32021100
Pulled By: jbschlosser
fbshipit-source-id: 0916bcaa77ef49545848b344d6385b33bacf473d
