Previously the test worked because the client was the last party to know
when encryption was established. However, due to changes in the TLSv1.3
handshake the server is now the last one.
In either case, relying on both to be encrypted when one of them is
finished is not great, so now we only quit the event loop when both
client and server have emitted 'encrypted'.
Change-Id: Ic1fc75671206d866f7ea983805fd58a99657aac6
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>
5134ff882a