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.
diff --git a/src/version.c b/src/version.c
index f6d5758..8d391d3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -756,6 +756,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    3098,
+/**/
     3097,
 /**/
     3096,