CameraITS: update ev compensation tests

1. basic test: always test [-2 ev, -1 ev, 0 ev, 1 ev, 2 ev]
2. advanced test: always test [-Max EV, ..., Max EV]
3. Allow images to be saturated for positive ev level

Change-Id: I138194c09f397ea1f1e96a1ef8ef8cf71ce0ed2c
2 files changed