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_fnameescape.vim b/src/testdir/test_fnameescape.vim
index cdff0df..5382b89 100644
--- a/src/testdir/test_fnameescape.vim
+++ b/src/testdir/test_fnameescape.vim
@@ -1,6 +1,6 @@
 
 " Test if fnameescape is correct for special chars like !
-function! Test_fnameescape()
+func Test_fnameescape()
   let fname = 'Xspa ce'
   let status = v:false
   try
@@ -18,4 +18,4 @@
   endtry
   call assert_true(status, "ExclamationMark")
   call delete(fname)
-endfunction
+endfunc