Fix: JVET_Z0054_BLK_REF_PIC_REORDER when DMVD is off
Add back mvpIdx signaling when DMVD is turned off by configure. Add back MVD sign prediction for AmvpMerge mode in case JVET_Y0129_MVD_SIGNAL_AMVP_MERGE_MODE is off.
NOTE: no impact on CTC.
Edited by Vadim Seregin