vp9: Some speed feature settings for speed 9.

vp9: Some speed feature settings for speed 9.

Disable 8x8 blocks for higher resolutions,
reduce mv_thresh for 1/2 subpel motion, and
disable golden reference at superblock level
based on source sad and motion content.

~6% loss in RTC metrics over current speed 9.
Speedup about ~10% for high motion clip on linux.

Change-Id: I7ff8f81ac93ee8a90d5a1f4837c955d000bd75e7