Limit cyclic refresh on steady background blocks.

Limit cyclic refresh on steady background blocks.

Use the existing QP condition on limiting cyclic refresh, and add
addiitonal condition that block has been encoded with zero/small motion
x frames in row (where x is at least several times the refresh period).
Additional condition only affect non-screen content mode.

This helps to improve visual stability for noisy input, where on steady
background areas the application of delta_qp may lead to encoding the noise.

Also added a change to use the true skip (after encoding) to update the
last QP.

Change-Id: I234a1128d017d284cf767fdb58ef6c59d809f679