Remove "best" deadline parameter from aomenc.

This option increases runtime by 20% and is only marginally
better than good cpu-used=0:

   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-0.3382 | -0.3911 | -0.4875 |  -0.2982 | -0.2992 | -0.3164 |    -0.3686

It is also not well integrated with speed_features.c, which is
the main reason for the removal.

Change-Id: If88c50367f63b860ad57f650869b978ec7734aad
diff --git a/av1/encoder/rdopt.c b/av1/encoder/rdopt.c
index 9157e5c..f938deb 100644
--- a/av1/encoder/rdopt.c
+++ b/av1/encoder/rdopt.c
@@ -6090,20 +6090,18 @@
            * and new motion search. */
           if (new_best_rd < label_mv_thresh) break;
 
-          if (cpi->oxcf.mode != BEST) {
 #if CONFIG_EXT_INTER
-            bsi->mvp.as_int = bsi->ref_mv[0]->as_int;
+          bsi->mvp.as_int = bsi->ref_mv[0]->as_int;
 #else
 // use previous block's result as next block's MV predictor.
 #if !CONFIG_REF_MV
-            if (index > 0) {
-              bsi->mvp.as_int = mi->bmi[index - 1].as_mv[0].as_int;
-              if (index == 2)
-                bsi->mvp.as_int = mi->bmi[index - 2].as_mv[0].as_int;
-            }
+          if (index > 0) {
+            bsi->mvp.as_int = mi->bmi[index - 1].as_mv[0].as_int;
+            if (index == 2)
+              bsi->mvp.as_int = mi->bmi[index - 2].as_mv[0].as_int;
+          }
 #endif  // !CONFIG_REF_MV
 #endif  // CONFIG_EXT_INTER
-          }
           max_mv = (index == 0) ? (int)x->max_mv_context[mbmi->ref_frame[0]]
                                 : AOMMAX(abs(bsi->mvp.as_mv.row),
                                          abs(bsi->mvp.as_mv.col)) >>