patch 8.0.0688: cannot resize the window in a FileType autocommand

Problem:    Cannot resize the window in a FileType autocommand. (Ingo Karkat)
Solution:   Add the CMDWIN flag to :resize. (test by Ingo Karkat,
            closes #1804)

src/testdir/test_quickfix.vim

@@ -2190,18 +2190,6 @@ func Test_bufoverflow()
   set efm&vim
 endfunc
 
-func Test_cclose_from_copen()
-    augroup QF_Test
-	au!
-        au FileType qf :call assert_fails(':cclose', 'E788')
-    augroup END
-    copen
-    augroup QF_Test
-	au!
-    augroup END
-    augroup! QF_Test
-endfunc
-
 " Tests for getting the quickfix stack size
 func XsizeTests(cchar)
   call s:setup_commands(a:cchar)
@@ -2231,6 +2219,18 @@ func Test_Qf_Size()
   call XsizeTests('l')
 endfunc
 
+func Test_cclose_from_copen()
+    augroup QF_Test
+	au!
+        au FileType qf :call assert_fails(':cclose', 'E788')
+    augroup END
+    copen
+    augroup QF_Test
+	au!
+    augroup END
+    augroup! QF_Test
+endfunc
+
 func Test_cclose_in_autocmd()
   " Problem is only triggered if "starting" is zero, so that the OptionsSet
   " event will be triggered.
@@ -2246,3 +2246,20 @@ func Test_cclose_in_autocmd()
   augroup! QF_Test
   call test_override('starting', 0)
 endfunc
+
+func Test_resize_from_copen()
+    augroup QF_Test
+	au!
+        au FileType qf resize 5
+    augroup END
+    try
+	" This should succeed without any exception.  No other buffers are
+	" involved in the autocmd.
+	copen
+    finally
+	augroup QF_Test
+	    au!
+	augroup END
+	augroup! QF_Test
+    endtry
+endfunc