Note that for initial sync to succeed, the initial sync node needs to create a backup cursor on the primary, which requires any backup cursors already on the primary are killed.

In SERVER-127978, we changed the failpoint that the initial sync node waited on.
We wanted to halt the initial sync node in the middle of its initial sync, but before it made a backup cursor, so we can kill the backup cursors on the primary first, and avoid a failed initial sync.

However, even though we kill the backup cursors here, we forgot to also do so here.