Modify encode breakout for static frames

Modify encode breakout for static frames

Thank Paul for the suggestions. While turning on static-thresh
for static-image videos, a big jump on bitrate was seen. In this
patch, we detected static frames in the video using first-pass
stats. For different cases, disable encode breakout or reduce
encode breakout threshold to limit the skipping.

More modification need be done to break incorrect partition
picking pattern for static frames while skipping happens.

Change-Id: Ia25f47041af0f04e229c70a0185e12b0ffa6047f