If a font with only a family set is resolved with one that has been setup
with setFamilies() then the family needs to be prepended to the families
list after resolving. This is so that the font still prefers the one set
as just a family with no famillies set.
This also amends the QFontDialog test to account for this too.
[ChangeLog][QtGui][Text] Resolving a font that just has a family set
with families set will prepend the family to the families so that it
is still the first preference for the font.
Task-number: QTBUG-46322
Change-Id: Icc4005732f95b2b4c684e592b06b31e133270e44
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>