Add NCOBMC_ADAPT_WEIGHT experiment flag

NCOBMC_ADAPT_WEIGHT allow using different interpolation kernels
to combine overlapped predictions generated using mvs in the
neighboring blocks.
This experiment will build on top of MOTION_VAR and it might conflict
with WARPED_MOTION in the developing stage, so will only be effective
when MOTION_VAR is on and WARPED_MOTION is off.

Change-Id: I4f1b6e55b6146ed443955751c09bfa22ef2f33e8

configure

@@ -323,6 +323,7 @@ EXPERIMENT_LIST="
     rect_intra_pred
     lgt
     sbl_symbol
+    ncobmc_adapt_weight
 "
 CONFIG_LIST="
     dependency_tracking
@@ -533,6 +534,8 @@ post_process_cmdline() {
     enabled chroma_sub8x8 && enable_feature cb4x4
     enabled compound_singleref && enable_feature ext_inter
     enabled new_multisymbol && enable_feature ec_adapt
+    enabled warped_motion && disable_feature ncobmc_adapt_weight
+    enabled ncobmc_adapt_weight && enable_feature motion_var
 
     if ! enabled delta_q && enabled ext_delta_q; then
       log_echo "ext_delta_q requires delta_q, so disabling ext_delta_q"