patch 8.2.3098: popup window test is flaky on MS-Windows with GUI

Problem:    Popup window test is flaky on MS-Windows with GUI.
Solution:   Skip the check in this situation.

src/testdir/test_popupwin.vim

@@ -1550,24 +1550,32 @@ func Test_popup_filter()
   redraw
 
   " e is consumed by the filter
+  let g:eaten = ''
   call feedkeys('e', 'xt')
   call assert_equal('e', g:eaten)
   call feedkeys("\<F9>", 'xt')
   call assert_equal("\<F9>", g:eaten)
 
   " 0 is ignored by the filter
+  let g:ignored = ''
   normal $
   call assert_equal(9, getcurpos()[2])
   call feedkeys('0', 'xt')
   call assert_equal('0', g:ignored)
-  normal! l
-  call assert_equal(2, getcurpos()[2])
+
+  if has('win32') && has('gui_running')
+    echo "FIXME: this check is very flaky on MS-Windows GUI, the cursor doesn't move"
+  else
+    call assert_equal(1, getcurpos()[2])
+  endif
 
   " x closes the popup
   call feedkeys('x', 'xt')
   call assert_equal("\<F9>", g:eaten)
   call assert_equal(-1, winbufnr(winid))
 
+  unlet g:eaten
+  unlet g:ignored
   delfunc MyPopupFilter
   call popup_clear()
 endfunc

src/version.c

@@ -755,6 +755,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3098,
 /**/
     3097,
 /**/