patch 8.0.1165: popup test is still flaky

Problem:    Popup test is still flaky.
Solution:   Add a term_wait() call. (Ozaki Kiichi)
diff --git a/src/testdir/test_popup.vim b/src/testdir/test_popup.vim
index 4ab860b..0dfa956 100644
--- a/src/testdir/test_popup.vim
+++ b/src/testdir/test_popup.vim
@@ -645,20 +645,26 @@
   endif
   let g:buf = term_start([$VIMPROG, '--clean', '-c', 'set noswapfile'], {'term_rows': h / 3})
   call term_sendkeys(g:buf, (h / 3 - 1)."o\<esc>G")
+  call term_wait(g:buf, 100)
   call term_sendkeys(g:buf, "i\<c-x>")
   call term_wait(g:buf, 100)
   call term_sendkeys(g:buf, "\<c-v>")
   call term_wait(g:buf, 100)
+  " popup first entry "!" must be at the top
   call WaitFor('term_getline(g:buf, 1) =~ "^!"')
   call assert_match('^!\s*$', term_getline(g:buf, 1))
   exe 'resize +' . (h - 1)
   call term_wait(g:buf, 100)
   redraw!
+  " popup shifted down, first line is now empty
   call WaitFor('term_getline(g:buf, 1) == ""')
   call assert_equal('', term_getline(g:buf, 1))
   sleep 100m
+  " popup is below cursor line and shows first match "!"
   call WaitFor('term_getline(g:buf, term_getcursor(g:buf)[0] + 1) =~ "^!"')
   call assert_match('^!\s*$', term_getline(g:buf, term_getcursor(g:buf)[0] + 1))
+  " cursor line also shows !
+  call assert_match('^!\s*$', term_getline(g:buf, term_getcursor(g:buf)[0]))
   bwipe!
 endfunc