patch 8.2.3508: Vim9: bad separators for "g" and "s" insufficiently tested

Problem:    Vim9: bad separators for "g" and "s" insufficiently tested.
Solution:   Add a few more test cases.

src/testdir/test_vim9_cmd.vim

@@ -1499,6 +1499,10 @@ def Test_var_not_cmd()
       g-pat-cmd
   END
   CheckDefAndScriptFailure(lines, 'E1241:', 1)
+  lines =<< trim END
+      g.pat.cmd
+  END
+  CheckDefAndScriptFailure2(lines, 'E1001: Variable not found: g', 'E121: Undefined variable: g', 1)
 
   lines =<< trim END
       s:notexist:repl
@@ -1509,6 +1513,10 @@ def Test_var_not_cmd()
       s-pat-repl
   END
   CheckDefAndScriptFailure(lines, 'E1241:', 1)
+  lines =<< trim END
+      s.pat.repl
+  END
+  CheckDefAndScriptFailure2(lines, 'E1001: Variable not found: s', 'E121: Undefined variable: s', 1)
 
   lines =<< trim END
       w:notexist->len()

src/version.c

@@ -757,6 +757,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3508,
 /**/
     3507,
 /**/