Moved tst_QImageReader::readText() and tst_QImageReader::preserveTexts()
behind QT_NO_IMAGEIO_TEXT_LOADING flag. The tests were failing on
webOS.
Fixes: QTBUG-99717
Pick-to: 6.3
Change-Id: Ib23decbaffe8d87c07fd68c41a28a3f7ca969cb1
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>