patch 8.0.0498: two autocmd tests are skipped on MS-Windows

Problem:    Two autocmd tests are skipped on MS-Windows.
Solution:   Make the test pass on MS-Windows. Write the messages in a file
            instead of getting the output of system().
diff --git a/src/version.c b/src/version.c
index 88fd23d..ba8ff84 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    498,
+/**/
     497,
 /**/
     496,