patch 8.1.1309: test for Normal highlight fails on MS-Windows GUI

Problem:    Test for Normal highlight fails on MS-Windows GUI.
Solution:   Skip the test for MS-Windows GUI.
diff --git a/src/version.c b/src/version.c
index 63cfd8d..b8acb8f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -768,6 +768,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1309,
+/**/
     1308,
 /**/
     1307,