Here we have an LGT to replace ADST for intra residual blocks, and
another LGT to replace ADST for inter residual blocks. The changes
are only applied to transform length 4 and 8, and only for the
lowbitdepth path.

lowres: -0.18%

Change-Id: Iadc1e02b53e3756b44f74ca648cfa8b0e8ca7af4