QFont::fromString incorrectly detects a font in strings with no commas.

The problem is here: https://code.woboq.org/qt5/qtbase/src/gui/text/qfont.cpp.html#_ZN5QFont10fromStringERK7QString

const auto l = descrip.splitRef(QLatin1Char(','));

should be

const auto l = descrip.splitRef(QLatin1Char(','), QString::SkipEmptyParts);

Presumably this is a bug, since the next few lines of this function test if count() == 0. And of course, please add tests for this function being passed empty strings. Super easy to encounter when reading from QSettings.

 It probably affects much more than just 5.13.0 and Windows, but that's all I tested.