patch 8.1.0357: instructions for tests are outdated

Problem:    Instructions for tests are outdated. (Jason Franklin)
Solution:   Update the text.
diff --git a/src/version.c b/src/version.c
index b3b4716..a594aa2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    357,
+/**/
     356,
 /**/
     355,