chore: separate base class members

Author: voltjia

src/base/avg_pool2d_backward_grad_input.h

@@ -33,14 +33,23 @@ class AvgPool2dBackwardGradInput : public Operator<AvgPool2dBackwardGradInput> {
 
  protected:
   Tensor::Shape grad_output_shape_;
+
   Tensor::Strides grad_output_strides_;
+
   DataType grad_output_type_;
+
   Tensor::Shape self_shape_;
+
   Tensor::Strides self_strides_;
+
   DataType self_type_;
+
   Tensor::Shape grad_input_shape_;
+
   Tensor::Strides grad_input_strides_;
+
   DataType grad_input_type_;
+
   int device_index_{0};
 };