Refine compound_type_rd based on model_rd for speed >= 4

Gate compound_type wedge and segment estimate_yrd_for_sb evaluation using model_rd value.

For speed 4 preset, BD-rate impact is seen as 0.00% (as per AWCY runs),
with encode time reduction of 3.00% (averaged across multiple test cases).

STATS_CHANGED
Change-Id: I6877f6d07707e4209ab882bbc2dd4390d7862fd3
diff --git a/av1/encoder/block.h b/av1/encoder/block.h
index 46947ec..7c4cd00 100644
--- a/av1/encoder/block.h
+++ b/av1/encoder/block.h
@@ -194,6 +194,7 @@
 typedef struct {
   int32_t rate[COMPOUND_TYPES];
   int64_t dist[COMPOUND_TYPES];
+  int64_t comp_model_rd[COMPOUND_TYPES];
   int_mv mv[2];
   MV_REFERENCE_FRAME ref_frames[2];
   PREDICTION_MODE mode;