idct test: use coeff consistently
idct test: use coeff consistently

Change-Id: I913a13066993a3315a0ff8310b3cad1572d4cdd7

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