We deprecated several setters on QSslSocket, no need to test
them then (and I'm removing them in Qt 6 anyway, so changing
the test is the phase 1).
Pick-to: 5.15
Change-Id: I5807abfb280cbacd4fcc19468793f9d1f3b2ff20
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>