patch 8.1.1666: click in popup window scrollbar with border doesn't scroll

Problem:    Click in popup window scrollbar with border doesn't scroll.
Solution:   Correct column for the border. (Naruhiko Nishino, closes #4650)
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 104ebd5..1a39d28 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -1580,6 +1580,7 @@
       call feedkeys("\<F4>\<LeftMouse>", "xt")
     endfunc
     func ClickBot()
+      call popup_setoptions(g:winid, {'border': [], 'close': 'button'})
       call feedkeys("\<F5>\<LeftMouse>", "xt")
     endfunc
     map <silent> <F3> :call test_setmouse(5, 36)<CR>