bpo-40275: Use new test.support helper submodules in tests (GH-21315)

diff --git a/Lib/test/test_msilib.py b/Lib/test/test_msilib.py
index 743bea7..e29cd4a 100644
--- a/Lib/test/test_msilib.py
+++ b/Lib/test/test_msilib.py
@@ -1,7 +1,8 @@
 """ Test suite for the code in msilib """
 import os
 import unittest
-from test.support import TESTFN, import_module, unlink
+from test.support.import_helper import import_module
+from test.support.os_helper import TESTFN, unlink
 msilib = import_module('msilib')
 import msilib.schema