Clean-up speed feature comp_inter_joint_search_thresh

This CL removes unused speed feature comp_inter_joint_search_thresh.

Change-Id: If401d60443544499694b27467500c7d778296613
diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index 5bf7aec..9d5b4de 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -918,7 +918,6 @@
     // clips (e.g. 5% loss on dinner_1080p). We need to examine the sequence a
     // bit more closely to figure out why.
     sf->inter_sf.adaptive_rd_thresh = 1;
-    sf->inter_sf.comp_inter_joint_search_thresh = BLOCK_SIZES_ALL;
     sf->inter_sf.disable_interinter_wedge_var_thresh = 100;
     sf->inter_sf.fast_interintra_wedge_search = 1;
     sf->inter_sf.prune_comp_search_by_single_result = boosted ? 4 : 1;
@@ -1274,7 +1273,6 @@
   sf->inter_sf.prune_ref_frame_for_rect_partitions = !boosted;
   sf->inter_sf.reduce_inter_modes = 1;
   sf->inter_sf.reuse_inter_intra_mode = 1;
-  sf->inter_sf.comp_inter_joint_search_thresh = BLOCK_SIZES_ALL;
   sf->inter_sf.disable_interinter_wedge_var_thresh = 100;
   sf->inter_sf.fast_wedge_sign_estimate = 1;
   sf->inter_sf.prune_comp_type_by_comp_avg = 2;
@@ -1652,7 +1650,6 @@
 }
 
 static AOM_INLINE void init_inter_sf(INTER_MODE_SPEED_FEATURES *inter_sf) {
-  inter_sf->comp_inter_joint_search_thresh = BLOCK_4X4;
   inter_sf->adaptive_rd_thresh = 0;
   inter_sf->model_based_post_interp_filter_breakout = 0;
   inter_sf->reduce_inter_modes = 0;
diff --git a/av1/encoder/speed_features.h b/av1/encoder/speed_features.h
index 77de5cc..954c512 100644
--- a/av1/encoder/speed_features.h
+++ b/av1/encoder/speed_features.h
@@ -794,12 +794,6 @@
   // same single inter mode as a group.
   int prune_comp_search_by_single_result;
 
-  // If 1 we iterate finding a best reference for 2 ref frames together - via
-  // a log search that iterates 4 times (check around mv for last for best
-  // error of combined predictor then check around mv for alt). If 0 we
-  // we just use the best motion vector found for each frame by itself.
-  BLOCK_SIZE comp_inter_joint_search_thresh;
-
   // Instead of performing a full MV search, do a simple translation first
   // and only perform a full MV search on the motion vectors that performed
   // well.