patch 9.0.0272: BufReadCmd not triggered when loading a "nofile" buffer

Problem:    BufReadCmd not triggered when loading a "nofile" buffer. (Maxim
            Kim)
Solution:   Call readfile() but bail out before reading a file.
            (closes #10983)
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 6bbe48c..c043a35 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -576,6 +576,18 @@
   au! BufReadCmd
 endfunc
 
+" BufReadCmd is triggered for a "nofile" buffer
+func Test_BufReadCmdNofile()
+  new somefile
+  set buftype=nofile
+  au BufReadCmd somefile call setline(1, 'triggered')
+  edit
+  call assert_equal('triggered', getline(1))
+
+  au! BufReadCmd
+  bwipe!
+endfunc
+
 func Test_augroup_deleted()
   " This caused a crash before E936 was introduced
   augroup x