vp9-svc: Fix to non-rd pickmode for screen content
vp9-svc: Fix to non-rd pickmode for screen content

For screen content mode: always force intra check
for spatially flat blocks that have moved. Also
adjust/fix condition for forcing check of
zeromv-golden for quality layers.
Reduces artifacts in screensharing tests.

Change-Id: Iafd62fb24a4e05f5b12af663dde2805fdb4c7b36

ShiftMediaProject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx,webmproject/libvpx,ShiftMediaProject/libvpx