Remove assert in QImageTextureGlyphCache::fillTexture()

The assert assumes that we are calculating the transformed bounds
of a glyph with exactly the same parameters as the image of the
glyph is later transformed.

However, when calculating the new bounding box of the glyph in
alphaMapBoundingBox, we do:

  t.mapRect(QRectF(gx, gy, gw, gh))

And then round the width and height up.

When we transform the image of the glyph, we do:

  t.mapRect(QRectF(0, 0, gw, gh)).toAlignedRect()

Note the origin is at origo and we align the rect. This can lead
to the actual transformed image sometimes being larger than what
is returned from alphaMapBoundingBox().

We could change alphaMapBoundingBox() to match the behavior of
the image transform, but it has a risk of missing some corner cases,
especially given that the same code paths are used for scalable
bitmap fonts.

In the end, just removing the assert is safe, since there is a
qMin() protecting against buffer overruns later, and there does
not seem to be any visual difference from actually calculating
the correct bounds.

[ChangeLog][Freetype] Fixed possible assert when transforming
bitmap fonts.

Pick-to: 6.5
Fixes: QTBUG-130930
Change-Id: I0406e6f45e0d436a5248dd986703bb3a9288b9f4
Reviewed-by: Paul Olav Tvete <paul.tvete@qt.io>
(cherry picked from commit fd75a66f3f65f6c8e8bfb933260676b5c18f2df1)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/gui/painting/qtextureglyphcache.cpp

@@ -309,8 +309,6 @@ void QImageTextureGlyphCache::fillTexture(const Coord &c,
         return;
     }
 #endif
-    Q_ASSERT(mask.width() <= c.w && mask.height() <= c.h);
-
     if (m_format == QFontEngine::Format_A32
         || m_format == QFontEngine::Format_ARGB) {
         QImage ref(m_image.bits() + (c.x * 4 + c.y * m_image.bytesPerLine()),