patch 8.1.2403: autocmd test fails under valgrind

Problem:    Autocmd test fails under valgrind.
Solution:   Wait a bit longer.
diff --git a/src/version.c b/src/version.c
index 8f098f2..f991cfb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -743,6 +743,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2403,
+/**/
     2402,
 /**/
     2401,