Remove call to clean grid filter from Clip

VTK-m's clip no longer copies all of the input points to the output.
Now, only the points that are actually part of the output are copied.
Therfore, the call to clean grid, which was there to remove the unused
points, is no longer required.

Accelerators/Vtkm/Filters/vtkmClipInstantiationsWithField.cxx

@@ -31,10 +31,6 @@ vtkm::cont::DataSet vtkmClip::internals::ExecuteClipWithField(vtkm::cont::DataSe
   fieldFilter.SetInvertClip(insideOut);
   auto result = fieldFilter.Execute(in);
 
-  // clean the output to remove unused points
-  vtkm::filter::clean_grid::CleanGrid clean;
-  result = clean.Execute(result);
-
   return result;
 }
 VTK_ABI_NAMESPACE_END

Accelerators/Vtkm/Filters/vtkmClipInstantiationsWithImplicitFunction.cxx

@@ -24,10 +24,6 @@ vtkm::cont::DataSet vtkmClip::internals::ExecuteClipWithImplicitFunction(
   functionFilter.SetInvertClip(insideOut);
   result = functionFilter.Execute(in);
 
-  // clean the output to remove unused points
-  vtkm::filter::clean_grid::CleanGrid clean;
-  result = clean.Execute(result);
-
   return result;
 }
 VTK_ABI_NAMESPACE_END