patch 8.0.0335: functions test fails

Problem:    Functions test fails.
Solution:   Use the right buffer number.
diff --git a/src/testdir/test_functions.vim b/src/testdir/test_functions.vim
index 5e34c2f..218567f 100644
--- a/src/testdir/test_functions.vim
+++ b/src/testdir/test_functions.vim
@@ -453,8 +453,8 @@
   call assert_equal(def_num, getbufvar(9, '', def_num))
   unlet def_num
 
-  call assert_equal(0, getbufvar(1, '&autoindent'))
-  call assert_equal(0, getbufvar(1, '&autoindent', 1))
+  call assert_equal(0, getbufvar(bnr, '&autoindent'))
+  call assert_equal(0, getbufvar(bnr, '&autoindent', 1))
 
   " Open new window with forced option values
   set fileformats=unix,dos