Migrate aom/master ANS test from d311d02.
Migrate aom/master ANS test from d311d02.

This helps in porting entropy coder changes that happened in aom/master.

Change-Id: If423eeb3da552066cceb88227138ea61d6a20f07
(cherry picked from aom/master commit d311d02da55433d20aad6dd88e0bbb992919988d)

mbebenita/aom,luctrudeau/aom,GrokImageCompression/aom,mbebenita/aom,mbebenita/aom,luctrudeau/aom,GrokImageCompression/aom,GrokImageCompression/aom,luctrudeau/aom,smarter/aom,mbebenita/aom,mbebenita/aom,mbebenita/aom,smarter/aom,luctrudeau/aom,luctrudeau/aom,mbebenita/aom,GrokImageCompression/aom,GrokImageCompression/aom,smarter/aom,mbebenita/aom,luctrudeau/aom,smarter/aom,smarter/aom,smarter/aom,GrokImageCompression/aom,mbebenita/aom