For VBR: (1) allow newmv mode for golden ref to
select interpolation filter (as in last ref case), and
(2) don't use the more aggressive tx-skip testing logic for large blocks.

Only affects 1 pass real-time vbr mode (speed >= 5).

PSNR/SSIM metrics on ytlive set are all positive, ~0.5-2% gain.

Change-Id: I0ffbb0a9755563a5acd6230c58236e4f19a47266