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.
diff --git a/src/version.c b/src/version.c
index a1e4a7f..2d99068 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    821,
+/**/
     820,
 /**/
     819,