Reduce intra_cost_penalty for BLOCK_8X8
Reduce intra_cost_penalty for BLOCK_8X8

This patch reduced the BLOCK_8X8's intra_cost_penalty, which
allows 8x8 blocks to conduct intra mode search. Borg test
result(rtc set): 0.077% PSNR gain, 0.228% SSIM gain. No speed
changes.

Change-Id: Icfe90c4f6969de24bda8ecacbd3da50330bf22b2

mwgoldsmith/vpx,luctrudeau/aom,mwgoldsmith/libvpx,webmproject/libvpx,shacklettbp/aom,zofuthan/libvpx,luctrudeau/aom,mbebenita/aom,mbebenita/aom,VTCSecureLLC/libvpx,felipebetancur/libvpx,openpeer/libvpx_new,ShiftMediaProject/libvpx,liqianggao/libvpx,smarter/aom,mbebenita/aom,Topopiccione/libvpx,running770/libvpx,Topopiccione/libvpx,felipebetancur/libvpx,Topopiccione/libvpx,mwgoldsmith/libvpx,thdav/aom,VTCSecureLLC/libvpx,goodleixiao/vpx,mwgoldsmith/libvpx,mbebenita/aom,mbebenita/aom,GrokImageCompression/aom,luctrudeau/aom,luctrudeau/aom,shacklettbp/aom,Topopiccione/libvpx,mwgoldsmith/vpx,mbebenita/aom,stewnorriss/libvpx,felipebetancur/libvpx,shyamalschandra/libvpx,openpeer/libvpx_new,goodleixiao/vpx,smarter/aom,thdav/aom,running770/libvpx,VTCSecureLLC/libvpx,webmproject/libvpx,smarter/aom,GrokImageCompression/aom,jmvalin/aom,goodleixiao/vpx,liqianggao/libvpx,zofuthan/libvpx,stewnorriss/libvpx,openpeer/libvpx_new,VTCSecureLLC/libvpx,smarter/aom,shacklettbp/aom,felipebetancur/libvpx,mwgoldsmith/libvpx,GrokImageCompression/aom,mwgoldsmith/libvpx,zofuthan/libvpx,VTCSecureLLC/libvpx,mwgoldsmith/vpx,ittiamvpx/libvpx-1,liqianggao/libvpx,webmproject/libvpx,shyamalschandra/libvpx,mwgoldsmith/vpx,ittiamvpx/libvpx-1,Topopiccione/libvpx,smarter/aom,stewnorriss/libvpx,zofuthan/libvpx,ittiamvpx/libvpx-1,stewnorriss/libvpx,ittiamvpx/libvpx-1,liqianggao/libvpx,thdav/aom,webmproject/libvpx,mwgoldsmith/vpx,shyamalschandra/libvpx,mbebenita/aom,webmproject/libvpx,luctrudeau/aom,zofuthan/libvpx,shyamalschandra/libvpx,shyamalschandra/libvpx,goodleixiao/vpx,thdav/aom,GrokImageCompression/aom,mbebenita/aom,jmvalin/aom,GrokImageCompression/aom,ShiftMediaProject/libvpx,ittiamvpx/libvpx-1,jmvalin/aom,ittiamvpx/libvpx-1,mbebenita/aom,ShiftMediaProject/libvpx,felipebetancur/libvpx,liqianggao/libvpx,zofuthan/libvpx,jmvalin/aom,VTCSecureLLC/libvpx,jmvalin/aom,thdav/aom,running770/libvpx,running770/libvpx,shacklettbp/aom,webmproject/libvpx,shacklettbp/aom,openpeer/libvpx_new,jmvalin/aom,stewnorriss/libvpx,smarter/aom,luctrudeau/aom,felipebetancur/libvpx,running770/libvpx,mwgoldsmith/libvpx,stewnorriss/libvpx,thdav/aom,liqianggao/libvpx,GrokImageCompression/aom,openpeer/libvpx_new,ShiftMediaProject/libvpx,ShiftMediaProject/libvpx,shyamalschandra/libvpx,openpeer/libvpx_new,mwgoldsmith/vpx,shacklettbp/aom,goodleixiao/vpx,Topopiccione/libvpx,goodleixiao/vpx,running770/libvpx