Since we added font matching by style name, the style name is not just
a derived property and should not be ignored in comparisons.
The QFontDef::exactMatch comparison is left unchanged, since it tests
if a loaded font matches a requested one.
Task-number: QTBUG-30851
Change-Id: I4187c5b993815001f35bcf24dc449059bfdcba6f
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@theqtcompany.com>