patch 8.2.2102: Vim9: not all error messages tested

Problem:    Vim9: not all error messages tested.
Solution:   Add a few test cases.
diff --git a/src/version.c b/src/version.c
index 56cea26..f023d97 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2102,
+/**/
     2101,
 /**/
     2100,