When EC_ADAPT is enabled, this patch uses the adapted CDF after
 encoding the entire frame to compute the non-adapted costs that are
 used in RDO decision making when coding the following frame.
Future patches will update these costs periodically while coding the
 frame to keep them in sync with the actual rates used when coding the
 symbols with the adapted CDF.

master@2017-06-30T01:10:29.197Z -> intra_cdfs@2017-06-30T01:09:41.171Z

   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-0.0168 |  0.0031 | -0.0181 |  -0.0018 | -0.0022 | -0.0209 |    -0.0027

Change-Id: Id9e284b429e4d2a31d418141af6935d7ece1180e