patch 8.2.0570: Vim9: no error when omitting type from argument

Problem:    Vim9: no error when omitting type from argument.
Solution:   Enforce specifying argument types.
diff --git a/src/testdir/test_vim9_func.vim b/src/testdir/test_vim9_func.vim
index f0b0ad0..8a6c3d6 100644
--- a/src/testdir/test_vim9_func.vim
+++ b/src/testdir/test_vim9_func.vim
@@ -250,6 +250,7 @@
 def Test_arg_type_wrong()
   CheckScriptFailure(['def Func3(items: list)', 'echo "a"', 'enddef'], 'E1008: Missing <type>')
   CheckScriptFailure(['def Func4(...)', 'echo "a"', 'enddef'], 'E1055: Missing name after ...')
+  CheckScriptFailure(['def Func5(items)', 'echo "a"'], 'E1077:')
 enddef
 
 def Test_vim9script_call()