Brings the following commit to aom:
b3ad8128 Port switch to 9-bit rate cost to vp10.

ntt-short1:

          MEDIUM (%)  HIGH (%)
    PSNR -0.078535   -0.398648
 PSNRHVS -0.416526   -0.468162
    SSIM -0.397539   -0.538516
FASTSSIM  0.008165    0.035524

subset1:

          RATE (%)  DSNR (dB)
    PSNR -0.00991   0.00063
 PSNRHVS  0.00115  -0.00009
    SSIM  0.01019  -0.00050
FASTSSIM  0.08721  -0.00279

Change-Id: I598ba7ee7efcde18439c31dfa96b86cbf297a580