vp9 frame parallel test: Initialize cfg differently
vp9 frame parallel test: Initialize cfg differently

Use the canonical 'vpx_codec_dec_cfg_t()' as opposed to 'vp9_zero()'
which just hammered everything to 0.

Change-Id: Id820efef700ad92a625797f8fd58e465b15eeca4

webmproject/libvpx,Topopiccione/libvpx,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,Topopiccione/libvpx,mwgoldsmith/libvpx,webmproject/libvpx,mwgoldsmith/libvpx,mwgoldsmith/libvpx,Topopiccione/libvpx,mwgoldsmith/vpx,webmproject/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/libvpx,mwgoldsmith/vpx,mwgoldsmith/vpx,webmproject/libvpx,Topopiccione/libvpx,mwgoldsmith/libvpx,mwgoldsmith/vpx,ShiftMediaProject/libvpx,mwgoldsmith/vpx,webmproject/libvpx,Topopiccione/libvpx,mwgoldsmith/vpx,ShiftMediaProject/libvpx,webmproject/libvpx,mwgoldsmith/libvpx,Topopiccione/libvpx