The stages $listClusterCatalog and $_internalListCollection are introduced after SERVER-96213.
Both stages rely on the extended test coverage of the core suite to verify the stage performs correctly under several options and background operations.

However, most of the aggregations stages are tested under jstests/aggregations/ which seems to have a dedicated extra coverage compared to the core case. 

Evaluate whether the core test for both stages could be moved/duplicated under jstests/aggregations.

Extra: Considering the jstests/aggregation is owned by query, we should have for CAR our own subfolder, as for example jstests/aggregations/catalog