QQuickTextControl: emit cursorPositionChanged() only if it changed

Change-Id: Id6fe03677e93119a63bfe87ade3cd333bf4890a1
Reviewed-by: Caroline Chao <caroline.chao@digia.com>
Reviewed-by: Pierre Rossi <pierre.rossi@gmail.com>
Re-enable qmltest on Mac

Only tst_fontloader.qml fails on Mac, and we have useful Qt.platform.os.

Task-number: QTBUG-25306
Change-Id: I6f4082028a188453378ad7ef73f51b1df2d89f11
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Disable textureinthread example when threaded gl is not available.

Task-number: QTBUG-30077
Change-Id: I8b6e4b8a33819fe84c843e85d863b582cfd69439
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>