patch 8.2.2107: Vim9: some errors not tested

Problem:    Vim9: some errors not tested.
Solution:   Add tests.  Fix getting the right error.
diff --git a/src/version.c b/src/version.c
index b0df924..8dba7a6 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2107,
+/**/
     2106,
 /**/
     2105,