The initial rescan now blocks any client connections. This means that

The initial rescan now blocks any client connections.  This means that
a deadlock is unlikely to arise in the initial scan.  It also means
that the server is not usable for a short period after startup (or
quite a long period after initial startup, but that's less of a
problem).

The tests now take advantage of this by waiting until the socket
appears before assuming the daemon has started.