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

diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 02509cd..7f30cac 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -1,5 +1,6 @@
 import unittest
 from test import support
+from test.support import import_helper
 import binascii
 import copy
 import pickle
@@ -7,7 +8,8 @@
 import sys
 from test.support import bigmemtest, _1G, _4G
 
-zlib = support.import_module('zlib')
+
+zlib = import_helper.import_module('zlib')
 
 requires_Compress_copy = unittest.skipUnless(
         hasattr(zlib.compressobj(), "copy"),