sad_test: create fn pointers w/'&' ref
sad_test: create fn pointers w/'&' ref

this helps some toolchains (vs9) resolve the type of the parameter

Change-Id: I4acc8a844d1e55b766f66482bd6d32998174d70f

thdav/aom,ittiamvpx/libvpx-1,luctrudeau/aom,luctrudeau/aom,shacklettbp/aom,mbebenita/aom,mwgoldsmith/libvpx,jmvalin/aom,luctrudeau/aom,Topopiccione/libvpx,GrokImageCompression/aom,mwgoldsmith/libvpx,mwgoldsmith/vpx,openpeer/libvpx_new,mbebenita/aom,openpeer/libvpx_new,ShiftMediaProject/libvpx,shacklettbp/aom,GrokImageCompression/aom,Topopiccione/libvpx,mbebenita/aom,shacklettbp/aom,webmproject/libvpx,ittiamvpx/libvpx-1,shacklettbp/aom,openpeer/libvpx_new,smarter/aom,mwgoldsmith/vpx,mwgoldsmith/vpx,jmvalin/aom,mwgoldsmith/libvpx,jmvalin/aom,ittiamvpx/libvpx-1,GrokImageCompression/aom,mbebenita/aom,mwgoldsmith/libvpx,webmproject/libvpx,mwgoldsmith/vpx,GrokImageCompression/aom,mwgoldsmith/vpx,webmproject/libvpx,smarter/aom,mbebenita/aom,thdav/aom,smarter/aom,GrokImageCompression/aom,smarter/aom,luctrudeau/aom,mbebenita/aom,mbebenita/aom,openpeer/libvpx_new,Topopiccione/libvpx,thdav/aom,webmproject/libvpx,luctrudeau/aom,Topopiccione/libvpx,ShiftMediaProject/libvpx,mwgoldsmith/libvpx,thdav/aom,luctrudeau/aom,ittiamvpx/libvpx-1,ShiftMediaProject/libvpx,ittiamvpx/libvpx-1,mwgoldsmith/vpx,shacklettbp/aom,Topopiccione/libvpx,smarter/aom,jmvalin/aom,Topopiccione/libvpx,jmvalin/aom,webmproject/libvpx,ShiftMediaProject/libvpx,thdav/aom,mbebenita/aom,ittiamvpx/libvpx-1,webmproject/libvpx,mbebenita/aom,GrokImageCompression/aom,thdav/aom,openpeer/libvpx_new,openpeer/libvpx_new,jmvalin/aom,ShiftMediaProject/libvpx,shacklettbp/aom,smarter/aom,mwgoldsmith/libvpx