patch 9.0.0958: messages test is flaky

Problem:    Messages test is flaky.
Solution:   Add a short delay.
diff --git a/src/version.c b/src/version.c
index 5d6a2a4..115c599 100644
--- a/src/version.c
+++ b/src/version.c
@@ -696,6 +696,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    958,
+/**/
     957,
 /**/
     956,