patch 8.0.1029: return value of getqflist() is inconsistent

Problem:    Return value of getqflist() is inconsistent.  (Lcd47)
Solution:   Always return an "items" entry.
diff --git a/src/testdir/test_quickfix.vim b/src/testdir/test_quickfix.vim
index 076d583..d6b65e3 100644
--- a/src/testdir/test_quickfix.vim
+++ b/src/testdir/test_quickfix.vim
@@ -2536,7 +2536,7 @@
   call assert_equal(30, l[1].lnum)
 
   call assert_equal({}, g:Xgetlist({'text' : 10}))
-  call assert_equal({}, g:Xgetlist({'text' : []}))
+  call assert_equal([], g:Xgetlist({'text' : []}).items)
 
   " Make sure that the quickfix stack is not modified
   call assert_equal(0, g:Xgetlist({'nr' : '$'}).nr)