patch 8.2.0465: Vim9: dead code and wrong return type

Problem:    Vim9: dead code and wrong return type.
Solution:   Remove dead code.  Fix return type.  Add more tests.
diff --git a/src/version.c b/src/version.c
index fdac01b..c33bf2c 100644
--- a/src/version.c
+++ b/src/version.c
@@ -739,6 +739,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    465,
+/**/
     464,
 /**/
     463,