test_intra_pred_speed: match above ext w/reconintra
test_intra_pred_speed: match above ext w/reconintra

only 2 x block_size is needed

+ remove a related TODO; C & assembly rely on this extension

Change-Id: Iea430267624251cccbbdaec8045eb81d01ae1db1

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