Extend prune_comp_search_by_single_result

Made the speed feature ‘prune_comp_search_by_single_result’ more aggressive
for cpu-used 2 for boosted frames.

cpu-used     Instruction count      Quality
                 reduction            drop
   2              1.67%              0.02%

STATS_CHANGED

Change-Id: If396d7ce055d4e224e834a5c1c9fcf5d38f83ea8

av1/encoder/speed_features.c

diff --git a/av1/encoder/speed_features.c b/av1/encoder/speed_features.c
index f7ba40b..1ff7003 100644
--- a/av1/encoder/speed_features.c
+++ b/av1/encoder/speed_features.c
@@ -378,6 +378,7 @@
     sf->disable_dual_filter = 1;
     sf->use_dist_wtd_comp_flag = DIST_WTD_COMP_DISABLED;
     sf->prune_comp_type_by_comp_avg = 2;
+    sf->prune_comp_search_by_single_result = boosted ? 4 : 1;
     // TODO(Sachin): Enable/Enhance this speed feature for speed 2 & 3
     sf->adaptive_interp_filter_search = 1;
     sf->perform_coeff_opt = is_boosted_arf2_bwd_type ? 2 : 3;