Bitmask patch 4: Store transform size info for vartx
Bitmask patch 4: Store transform size info for vartx

To store tx_size information, instead of advancing by 4x4 step
vertically and tx_size step horizontally (for vertical edges,
similar to horizontal edges), follow recursion in vartx parsing.

Benefit:
Suppose the block is 32x32 with transform sizes 16x16, the original
traversal needs 8*2(vertical) + 8*2(horizontal) = 32 steps.
Now, it needs 4 steps.

Change-Id: I0a9154e2943107613b4b2fcda47324aafb3a7c80

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