Size changes do not warrant a transform update.

The size is not a part of the matrix, so the matrix does
not need to be recomputed when the size of an element changes.
The exception from this is when using transform origin which
is already specialcased in the QQuickWindow::updateDirtyNode()
function.

Change-Id: I2c517880d39aa69232974f65da93333b7cba341d
Reviewed-by: Alan Alpert <aalpert@blackberry.com>