patch 8.2.2980: popup window test is a bit flaky

Problem:    Popup window test is a bit flaky.
Solution:   Add a redraw command.

src/testdir/test_popupwin.vim

@@ -1552,6 +1552,7 @@ func Test_popup_filter()
   call assert_equal(9, getcurpos()[2])
   call feedkeys('0', 'xt')
   call assert_equal('0', g:ignored)
+  redraw
   call assert_equal(1, getcurpos()[2])
 
   " x closes the popup

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2980,
 /**/
     2979,
 /**/