Freetype Windows font backend reports wrong font weight

With the Freetype font backend, the following should report font weight 900 but currently reports font weight 400:

QFont font("Arial Black");
font.setStyleName("Black");
QFontInfo fontInfo(font);
qDebug() << fontInfo.weight();

To run this code with the Freetype backend, add command line parameter -platform windows:fontengine=freetype when running the executable.

The issue was discovered in this code review comment: https://codereview.qt-project.org/c/qt/qtbase/+/399156/comment/6e62c91f_f07ac3c2/

The code works fine with the GDI backend if you change setStyleName("Black") to setStyleName("Regular") and apply this patch. (The styleName change is necessary because Freetype registers the font as family/subfamily "Arial Black"/"Black" whereas GDI treats it as "Arial Black"/"Regular". This inconsistency was also discovered in the code review comment linked above but wasn't seen as critical.)

Reproduction

More extensive code example attached.

Can also be tested with the tst_QFontDatabase::subFamilyMatching() test from https://codereview.qt-project.org/c/qt/qtbase/+/399156. The test should be adjusted after fixing this bug.