test: end tls connection with some data

In openssl-1.1.1e the client doesn't seem to like having the TLS
connection shut down with no data sent, so send an empty string. A
number of related issues showed up in the TLS1.3 port, so this is
not entirely surprising.

PR-URL: https://github.com/nodejs/node/pull/32328
Fixes: https://github.com/nodejs/node/issues/32210


Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>