Correctly update flickable visibleArea.heightRatio when geometry changes

Without this fix the visibleArea.heightRatio and widthRatio values
were only updated on geometry changes when flicking was active.

So when setting the flickable geometry to the content geometry and
thereby disabling flicking the ratios were not updated.

This could for example cause wrong scrollbar renderings.

The ratios are now also calculated directly after accessing the
visibleArea property for the first time.

The new autotest covers both problems.

Change-Id: I54ba606524557fb328a198c312c1f65eb125c5a3
Reviewed-by: Alan Alpert <aalpert@blackberry.com>
Add diagnostic output to tst_qquickpathview::cancelDrag().

Task-number: QTBUG-32662
Change-Id: I62b53f94659be95b3bef86f853733998d4d882dc
Reviewed-by: Simo Fält <simo.falt@digia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>
Stabilize tst_qquickitem.

Instantiate windows and views on the stack or add
QScopedPointer. Add waitForWindowExposed() after show().
Add diagnostic message.

Task-number: QTBUG-32664
Change-Id: I190f2a0490b8333a7886a23e26582c6cb615df94
Reviewed-by: Simo Fält <simo.falt@digia.com>
Reviewed-by: Sergio Ahumada <sergio.ahumada@digia.com>