It fails on CI (Windows 10). Given our qabstractsocket disables
read notifications/stops emitting readyRead if it already has pending data
(unbuffered, aka UDP socket type) - make sure we do not suffer from this.
The change does not affect the test's logic (unless the logic was to fail),
it just makes it more fail-proof.
Change-Id: I6c9b7ded20478f675260872a2a7032b4f356f197
Fixes: QTBUG-73884
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>