Text may overlapped printing on Linux

For some fonts with sub glyphs, the QFontEngineFT::getUnscaledGlyph may get unwanted metrics for some glyphs, this cause text overlapped when printing on Linux platform.

See the below code for example:

		QFont font("DFKai-SB", 32);
		painter.setFont(font);

		QRect rect(0, 0, dev->width(), dev->height());
		painter.drawText(rect, Qt::AlignCenter, QString::fromUtf16(u"校園"));

When printing or uses QPdfWriter as QPaintDevice, the 校園 overlapped.

I have no idea how to fix the FT_Load_Glyph(face, glyph, FT_LOAD_NO_BITMAP) called in QFontEngineFT::getUnscaledGlyph.

If you use fontforge open the pdf file, you will see the "園" position not place center compare on the origin font.