patch 8.1.2011: more functions can be used as methods

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.  Make the window
            command test faster.
diff --git a/src/testdir/test_assert.vim b/src/testdir/test_assert.vim
index d89bd98..1b1f9e5 100644
--- a/src/testdir/test_assert.vim
+++ b/src/testdir/test_assert.vim
@@ -259,7 +259,7 @@
 
 func Test_override()
   call test_override('char_avail', 1)
-  call test_override('redraw', 1)
+  eval 1->test_override('redraw')
   call test_override('ALL', 0)
   call assert_fails("call test_override('xxx', 1)", 'E475')
   call assert_fails("call test_override('redraw', 'yes')", 'E474')