[CustomOP unittest] Remove useless comment in custom operator's unit test (#52710)

test/custom_op/custom_relu_op.cc

@@ -94,8 +94,6 @@ std::vector<paddle::Tensor> relu_cpu_double_backward(
                                    ddout.size());
                              }));
 
-  std::cout << "Debug info: run relu cpu double backward success." << std::endl;
-
   return {ddout};
 }
 

test/custom_op/custom_relu_op.cu

@@ -113,8 +113,6 @@ std::vector<paddle::Tensor> relu_cuda_double_backward(
                 numel);
       }));
 
-  std::cout << "Debug info: run relu gpu double backward success." << std::endl;
-
   return {ddout};
 }
 

test/custom_op/custom_relu_op_xpu.cc

@@ -96,8 +96,6 @@ std::vector<paddle::Tensor> relu_cpu_double_backward(
                                    ddout.size());
                              }));
 
-  std::cout << "Debug info: run relu cpu double backward success." << std::endl;
-
   return {ddout};
 }
 
@@ -136,8 +134,6 @@ std::vector<paddle::Tensor> relu_xpu_double_backward(
 
   ddout = paddle::multiply(ddx, paddle::where(condition, ones, zeros));
 
-  std::cout << "Debug info: run relu cpu double backward success." << std::endl;
-
   return {ddout};
 }