compositeRefEnabled is an encoder only option. It should not be stored in the SPS.
This commit is the last to remove unused parameters from SPSNext. Thus also
all comments related to SPSNext are removed.

IBC block search history status is not reset for each frame, which may affect IBC searching results for the second frame.

JVET-M0247 1. Add early termination and encoder search method. 2. Only enable it for RA configuration.