The "good" speed levels are universally better than the "rt" ones,
running faster to achieve the same quality.

rt mode also turned off alt refs and lag-in-frames, but these
are still accessible separately (and the low latency test case
explicitly sets them).

Some features were used by the rt scale and not the good scale.
Two additional "good" levels, 7 and 8, were added to accomidate
these features and not reduce test coverage.

Change-Id: I3a6a78ddb664511762c197bc41f3a9909665b565