This is a partial revert of commit
f385b882.

This causes issues because we may overwrite genuine styles with
synthetic ones.

Lets say for instance that we register "Roboto Bold" and then later
we register "Roboto Thin". When we register "Roboto Thin" we also
register an alternative font which is called "Roboto" (because this
is the typographical family name of the font) with bold weight, because
we know Windows can synthesize this.

This would work fine, except that on Windows we also store the original
face name of the font as a user-pointer in the database. This contains
the legacy name of the font: "Roboto Thin". This will override the
font that is already stored. When we look up "Roboto" + bold weight in
the database later, we will find this synthetic font, replace
the requested family name with the legacy one "Roboto Thin" and use
this instead.

The right fix for now is to revert the cause of the regression. If we
want to re-fix the original bug, we might be able to reintroduce
f385b882

 and then make sure we always
prefer the "real" font when there are conflicts (this would mean marking
synthetic fonts in the database).

[ChangeLog][Windows] Fixed a regression where different font styles
and/or weights would not be available.

Fixes: QTBUG-94781
Task-number: QTBUG-91398
Pick-to: 5.15 6.1 6.2
Change-Id: I092022b14ebf1d56685eaa3b8efe55f015659adc
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>