Refine/clean up scan orders
Refine/clean up scan orders

Inter scan orders for 4x4, 8x8, 16x16 are modified to use
row/col scans for DCT_ADST combinations.
New 4:1 transforms 4x16/16x4 use row col scans
for DCT_ADST combinations.
The h2, v2, qtr scans are removed for 32x32, since they are
not used.

Change-Id: I4dab6b111858e14b3c5b92b5c46124c69e06808d

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom