patch 8.2.3859: Vim9: some code lines not tested

Problem:    Vim9: some code lines not tested.
Solution:   Add a few specific tests.
diff --git a/src/testdir/test_vim9_cmd.vim b/src/testdir/test_vim9_cmd.vim
index 2d86b6b..6347a28 100644
--- a/src/testdir/test_vim9_cmd.vim
+++ b/src/testdir/test_vim9_cmd.vim
@@ -1392,6 +1392,10 @@
   s:theList[1] = 44
   assert_equal([1, 44, 3], s:theList)
 
+  if 0
+    lockvar whatever
+  endif
+
   var d = {a: 1, b: 2}
   d.a = 3
   d.b = 4
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index af80935..fe985de 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -2963,7 +2963,7 @@
 
 def Test_for_loop_script_var()
   # cannot use s:var in a :def function
-  CheckDefFailure(['for s:var in range(3)', 'echo 3'], 'E461:')
+  CheckDefFailure(['for s:var in range(3)', 'echo 3'], 'E1254:')
 
   # can use s:var in Vim9 script, with or without s:
   var lines =<< trim END