patch 8.2.2127: Vim9: executing user command from Vim9 script not tested

Problem:    Vim9: executing user command defined in Vim9 script not tested.
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index 491ea90..1a534ee 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2127,
+/**/
     2126,
 /**/
     2125,