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_options.vim b/src/testdir/test_options.vim
index 5d5723c..3a43356 100644
--- a/src/testdir/test_options.vim
+++ b/src/testdir/test_options.vim
@@ -510,7 +510,7 @@
   call assert_true(empty(execute('bn', '')))
   call assert_false(test_getvalue('need_fileinfo'))
   call assert_true(empty(execute('bn', '')))
-  call assert_false(test_getvalue('need_fileinfo'))
+  call assert_false('need_fileinfo'->test_getvalue())
   set hidden
   call assert_true(empty(execute('bn', '')))
   call assert_false(test_getvalue('need_fileinfo'))