patch 8.2.0821: Vim9: memory leak in expr test

Problem:    Vim9: memory leak in expr test.
Solution:   Do not decrement the length of the list of functions if the
            current function is not at the end.

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    821,
 /**/
     820,
 /**/