patch 8.1.1804: no test for display updating without a scroll region

Problem:    No test for display updating without a scroll region.
Solution:   Add a test.
diff --git a/src/version.c b/src/version.c
index 5e027dd..d249d85 100644
--- a/src/version.c
+++ b/src/version.c
@@ -774,6 +774,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1804,
+/**/
     1803,
 /**/
     1802,