The AsyncResultsMerger currently has some dependencies that are sharding specific. The goal is to remove those sharding specific dependencies and move the async_results_merger library out of the sharding directory. As part of SERVER-29617, the last piece of sharding logic was removed from the ARM implementation, but there are still a few remnants lying around that make the ARM appear to be a sharding component. For example, the AsyncResultsMerger::RemoteCursorData::getShard method still exists, and the ClusterClientCursorParams::RemoteCursor struct still has a ShardId field. Since the ARM is now used in the Replication system's CollectionCloner as well as for sharded cluster commands, we should get rid of these sharding specific details, so the ARM can continue to be used in a generic fashion. It would additionally be helpful if the code comments were updated as well, to get rid of any sharding specific language.