patch 8.0.0486: crash and endless loop when closing windows in autocmd

Problem:    Crash and endless loop when closing windows in a SessionLoadPost
            autocommand.
Solution:   Check for valid tabpage.  (partly neovim #6308)
diff --git a/src/version.c b/src/version.c
index 91f795b..7cd12eb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    486,
+/**/
     485,
 /**/
     484,