patch 8.1.1379: filechanged test hangs

Problem:    Filechanged test hangs.
Solution:   Do not check 'autoread'.
diff --git a/src/testdir/test_filechanged.vim b/src/testdir/test_filechanged.vim
index ce78609..a937bb8 100644
--- a/src/testdir/test_filechanged.vim
+++ b/src/testdir/test_filechanged.vim
@@ -115,8 +115,9 @@
   call assert_match('E211:', v:warningmsg)
   call assert_equal(2, line('$'))
   call assert_equal('extra line', getline(2))
+  let v:warningmsg = 'empty'
 
-  " Recreate buffer and reload
+  " change buffer, recreate the file and reload
   call setline(1, 'buffer is changed')
   silent !echo 'new line' >Xchanged_d
   call feedkeys('L', 'L')