patch 8.1.0711: test files still use function!

Problem:    Test files still use function!.
Solution:   Remove the exclamation mark.  Fix overwriting a function.
diff --git a/src/testdir/test_messages.vim b/src/testdir/test_messages.vim
index 0a7f3f5..4bdc136 100644
--- a/src/testdir/test_messages.vim
+++ b/src/testdir/test_messages.vim
@@ -43,7 +43,7 @@
 " indicator (e.g., "-- INSERT --") when ":stopinsert" is invoked.  Message
 " output could then be disturbed when 'cmdheight' was greater than one.
 " This test ensures that the bugfix for this issue remains in place.
-function! Test_stopinsert_does_not_break_message_output()
+func Test_stopinsert_does_not_break_message_output()
   set cmdheight=2
   redraw!
 
@@ -58,7 +58,7 @@
   redraw!
 
   set cmdheight&
-endfunction
+endfunc
 
 func Test_message_completion()
   call feedkeys(":message \<C-A>\<C-B>\"\<CR>", 'tx')