ENH: Increase itk::DiscreteGaussianCurvatureQuadEdgeMeshFilter coverage

Increase coverage for
`itk::DiscreteGaussianCurvatureQuadEdgeMeshFilter`: exercise basic
object methods using the `ITK_EXERCISE_BASIC_OBJECT_METHODS` macro,
and remove the inconsequential call to print the filter at the end of
the test: rely on the basic method exercising macro call.

Modules/Filtering/QuadEdgeMeshFiltering/test/itkDiscreteGaussianCurvatureQuadEdgeMeshFilterTest.cxx

@@ -52,6 +52,10 @@ itkDiscreteGaussianCurvatureQuadEdgeMeshFilterTest(int argc, char * argv[])
 
   auto gaussianCurvatureFilter = CurvatureFilterType::New();
 
+  ITK_EXERCISE_BASIC_OBJECT_METHODS(
+    gaussianCurvatureFilter, DiscreteGaussianCurvatureQuadEdgeMeshFilter, DiscreteCurvatureQuadEdgeMeshFilter);
+
+
   gaussianCurvatureFilter->SetInput(mesh);
   gaussianCurvatureFilter->Update();
 
@@ -63,8 +67,6 @@ itkDiscreteGaussianCurvatureQuadEdgeMeshFilterTest(int argc, char * argv[])
   writer->SetFileName("gaussian_curvature.vtk");
   writer->Update();
 
-  // ** PRINT **
-  std::cout << gaussianCurvatureFilter;
 
   std::cout << "Test finished." << std::endl;
   return EXIT_SUCCESS;