Unsupported derivative reduce_window

[wsmoses]

error: Unsupported reduce window rev autodiff(1): 
%8 = "stablehlo.reduce_window"(%7, %2) <{padding = dense<[[2, 2], [2, 2], [0, 0], [0, 0]]> : tensor<4x2xi64>, window_dilations = array<i64: 1, 1, 1, 1>, window_dimensions = array<i64: 5, 5, 1, 1>, window_strides = array<i64: 5, 5, 1, 1>}> ({
^bb0(%arg5: tensor<f32>, %arg6: tensor<f32>):
  %13 = "stablehlo.add"(%arg5, %arg6) : (tensor<f32>, tensor<f32>) -> tensor<f32>
  "stablehlo.return"(%13) : (tensor<f32>) -> ()
}) : (tensor<5x5x2x2xf32>, tensor<f32>) -> tensor<1x1x2x2xf32>

@Pangoraw mind giving it a try?

[Pangoraw]

That's from meanpooling, I'll give it a go. In the worst case, I think we can consider this as a convolution with a kernel filled with 1s.