patch 8.1.1455: popup_atcursor() not completely implemented

Problem:    Popup_atcursor() not completely implemented.
Solution:   Add the default for the "moved" property.
diff --git a/src/testdir/test_popupwin.vim b/src/testdir/test_popupwin.vim
index 6d3279b..50165ec 100644
--- a/src/testdir/test_popupwin.vim
+++ b/src/testdir/test_popupwin.vim
@@ -1009,8 +1009,9 @@
   call assert_equal({}, popup_getpos(winid))
   popupclear
 
+  " WORD is the default
   exe "normal gg0/WORD\<CR>"
-  let winid = popup_atcursor('text', {'moved': 'WORD'})
+  let winid = popup_atcursor('text', {})
   redraw
   call assert_equal(1, popup_getpos(winid).visible)
   call feedkeys("eli\<Esc>", 'xt')