patch 8.0.1595: no autocommand triggered before exiting

Problem:    No autocommand triggered before exiting.
Solution:   Add the ExitPre autocommand event.
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index e3230c5..159bf1e 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -97,6 +97,7 @@
 	    test_exec_while_if.res \
 	    test_exists.res \
 	    test_exists_autocmd.res \
+	    test_exit.res \
 	    test_farsi.res \
 	    test_file_size.res \
 	    test_find_complete.res \