patch 8.1.1051: not all ways to switch terminal mode are tested

Problem:    Not all ways to switch terminal mode are tested.
Solution:   Add more test cases.
diff --git a/src/version.c b/src/version.c
index f449642..13db401 100644
--- a/src/version.c
+++ b/src/version.c
@@ -776,6 +776,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1051,
+/**/
     1050,
 /**/
     1049,