patch 8.2.4331: Vim9: no test for existing script variable in block

Problem:    Vim9: no test for existing script variable in block.
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index d7da6df..e0bb6e1 100644
--- a/src/version.c
+++ b/src/version.c
@@ -747,6 +747,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    4331,
+/**/
     4330,
 /**/
     4329,