patch 8.2.0318: Vim9: types not sufficiently tested

Problem:    Vim9: types not sufficiently tested.
Solution:   Add tests with more types.
diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index fb7d39f..5ece652 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -861,4 +861,8 @@
   call CheckDefExecFailure("CallMe ('yes')", 'E492:')
   call CheckDefFailure("CallMe2('yes','no')", 'E1069:')
   call CheckDefFailure("CallMe2('yes' , 'no')", 'E1068:')
+
+  call CheckDefFailure("v:nosuch += 3", 'E1001:')
+  call CheckDefFailure("let v:version = 3", 'E1064:')
+  call CheckDefFailure("let asdf = v:nosuch", 'E1001:')
 endfunc