noop reduce window

```mlir %cst = stablehlo.constant dense<0.000000e+00> : tensor<f64> %1 = "stablehlo.reduce_window"(%0, %cst) <{base_dilations = array<i64: 1, 1, 1>, padding = dense<0> : tensor<3x2xi64>, window_dilations = array<i64: 1, 1, 1>, window_dimensions = array<i64: 1, 1, 1>, window_strides = array<i64: 1, 1, 1>}> ({ ^bb0(%arg18: tensor<f64>, %arg19: tensor<f64>): %3 = stablehlo.add %arg18, %arg19 : tensor<f64> stablehlo.return %3 : tensor<f64> }) : (tensor<4x752x1520xf64>, tensor<f64>) -> tensor<4x752x1520xf64>