Check off-by-one in minimumRightBearing on Windows

The underlying reason for QTBUG-84415 is that the actual minimum right bearing (maximum negative right bearing) of glyphs is sometimes less than the minimum right bearing reported by the font. This causes the QTextLayout to make lines which may be wider than the max.

Since the observed difference was 1 pixel and it only happens when using GDI, it is possible that this is caused by font hinting, because the minimum right bearing is extracted directly from font data and refers to design metrics. An easy fix, if true, would be to account for the extra pixel in the condition in QTextLayout.

So the task is to investigate whether this suspicion is correct and fix QTextLayout if necessary.