Fix Rendering order issue when 3D layer render translucent

Fix Rendering order issue when 3D layer render translucent

Sort rendering-order by Euclidean distance for special case.

Previously, we only check ModelView's translation z-value.
But if we use perspective projectoin camera, the distance might not
be fit as human sense.

Now, when layer is 3D and camera is perspective projection mode,
let we use zValue as Euclidean distance.

It cannot resolve translucent object's rendering order issue
perfectly. But can resolve some case.

Change-Id: Ie33cc5cfd338ff001b18885026a4daf779227b0e
Signed-off-by: Eunki, Hong <eunkiki.hong@samsung.com>