patch 9.0.0617: calling function for reduce() has too much overhead

Problem:    Calling function for reduce() has too much overhead.
Solution:   Only call clear_tv() when needed.

src/version.c

@@ -699,6 +699,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    617,
 /**/
     616,
 /**/