patch 9.0.0406: deferred functions not invoked when partial func exits

Problem:    Deferred functions not invoked when partial func exits.
Solution:   Create a funccall_T when calling a :def function.

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    406,
 /**/
     405,
 /**/