Add a partition search breakout model

Add a partition search breakout model

for q-index between 150 and 200.

Previously the ML based breakout feature is only supported for q-index
larger than 200.

This only affects speed 1 and 2, resolution under 720p, q-index between
150 and 200, low bit-depth.

Compression performane change is neutral.
Encoding speed gain is up to 30% for speed 1;
                       up to 20% for speed 2.

Results from encoding city_4cif_30fps:
speed 1, QP=38
before:  37.689 dB, 41007b/f, 2.91 fps
after:   37.687 dB, 40998b/f, 3.46 fps

speed 1, QP=48
before:  35.959 dB, 22106b/f, 3.66 fps
after:   35.950 dB, 22118b/f, 4.83 fps

speed 2, QP=38
before:  37.630 dB, 40999b/f, 4.42 fps
after:   37.633 dB, 41063b/f, 4.63 fps

speed 2, QP=48
before:  35.905 dB, 22177b/f, 4.90 fps
after:   35.889 dB, 22145b/f, 5.92 fps

Change-Id: Ibd4a2f4d7093fb248ab94ddd388cbaa8de2c5ef7