patch 8.1.2421: test88 is old style

Problem:    Test88 is old style.
Solution:   Turn into a new style test. (Yegappan Lakshmanan, closes #5347)
diff --git a/src/testdir/Make_vms.mms b/src/testdir/Make_vms.mms
index f48a3cd..e31060b 100644
--- a/src/testdir/Make_vms.mms
+++ b/src/testdir/Make_vms.mms
@@ -76,7 +76,7 @@
 SCRIPT = test1.out \
        test42.out test44.out test49.out \
        test64.out test69.out \
-       test72.out test77a.out test88.out \
+       test72.out test77a.out \
        test95.out test99.out \
        test_eval.out