patch 8.1.1952: more functions can be used as a method

Problem:    More functions can be used as a method.
Solution:   Allow more functions to be used as a method.
diff --git a/src/testdir/test_terminal.vim b/src/testdir/test_terminal.vim
index e173b42..39956ba 100644
--- a/src/testdir/test_terminal.vim
+++ b/src/testdir/test_terminal.vim
@@ -2066,6 +2066,9 @@
   " In the GUI it can be more, let's assume a 20 x 14 cell.
   " And then add 100 / 200 tolerance.
   let [xroot, yroot] = getwinpos()
+  let winpos = 50->getwinpos()
+  call assert_equal(xroot, winpos[0])
+  call assert_equal(yroot, winpos[1])
   let [winrow, wincol] = win_screenpos('.')
   let xoff = wincol * (has('gui_running') ? 14 : 7) + 100
   let yoff = winrow * (has('gui_running') ? 20 : 10) + 200