patch 7.4.1727
Problem:    Cannot detect a crash in tests when caused by garbagecollect().
Solution:   Add garbagecollect_for_testing().  Do not free a job if is still
            useful.
diff --git a/src/main.c b/src/main.c
index dc7b702..ee37500 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1531,7 +1531,7 @@
 #endif
 #ifdef FEAT_EVAL
     if (garbage_collect_at_exit)
-	garbage_collect();
+	garbage_collect(FALSE);
 #endif
 #if defined(WIN32) && defined(FEAT_MBYTE)
     free_cmd_argsW();