Generate glyphs in un-transformed coordinate system.

Generate glyphs in un-transformed coordinate system.

Avoids rounding issues with very large coordinates.

Task-number: QTBUG-21262 - QRasterPaintEngine & QFontEngineFT - fonts corrupted when scrolling to the bottom of long texts
Reviewed-by: Eskil
Signed-off-by: Aleksandar Stojiljkovic <aleksandar.stojiljkovic@nokia.com>
(cherry picked from commit 43e013e2048e8193e2d31276cac6348a9f6ce340)

Change-Id: I5810a1a60f2bbdba4889a6b5e493b183018f3976
Reviewed-on: http://codereview.qt-project.org/5202
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>