qSqrt of negative argument in QFontEngineFT::loadTransformedGlyphSet

There is a call of qSqrt inside the function QFontEngineFT::loadTransformedGlyphSet:

bool draw_as_outline = fontDef.pixelSize * qSqrt(matrix.det()) >= 64;

(line 1371 of file src/gui/text/qfontengine_ft.cpp)

The argument of qSqrt can be negative if matrix contains reflection. However we need
only absolute value of matrix.det() here. Therefore we have to put matrix.det() inside qAbs:

bool draw_as_outline = fontDef.pixelSize * qSqrt( qAbs( matrix.det())) >= 64;