Fix motion vector crashes with particles, skinning and morphing

Exclude blend particle models and instanced models without instances
from the motion vector pass, and use the current frame data as previous
frame data on the first tracked frame.

Pick-to: 6.12 6.11
Change-Id: I3d1640696fbe946a5d2f5d8b0161ec8e82e07808
Reviewed-by: Tomi Korpipaa <tomi.korpipaa@qt.io>
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
Reviewed-by: Antti Määttä <antti.maatta@qt.io>