patch 8.1.0119: failing test goes unnoticed because messages is not written

Problem:    Failing test goes unnoticed because testdir/messages is not
            written.
Solution:   Set 'nomodifiable' only local to the buffer.
diff --git a/src/version.c b/src/version.c
index ff3806a..a7a96b3 100644
--- a/src/version.c
+++ b/src/version.c
@@ -790,6 +790,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    119,
+/**/
     118,
 /**/
     117,