patch 8.2.4834: Vim9: some lines not covered by tests

Problem:    Vim9: some lines not covered by tests.
Solution:   Add a few more tests.  Remove dead code.

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4834,
 /**/
     4833,
 /**/