This part of the test attempts to prove that a mongos can discover through the shard versioning protocol when an unsharded collection is dropped, movePrimary occurs, and the collection is recreated.

This is not expected to work, but the test passes because the test asserts that a stale mongos (one that believes the collection is still on the old primary shard) can see writes done by a fellow stale mongos (also believes collection is still on the old primary shard).

The movePrimary was done from a third mongos.