bpo-40275: Use new test.support helper submodules in tests (GH-21317)

diff --git a/Lib/test/test_hashlib.py b/Lib/test/test_hashlib.py
index ba90298..4551011 100644
--- a/Lib/test/test_hashlib.py
+++ b/Lib/test/test_hashlib.py
@@ -18,7 +18,8 @@
 import unittest
 import warnings
 from test import support
-from test.support import _4G, bigmemtest, import_fresh_module
+from test.support import _4G, bigmemtest
+from test.support.import_helper import import_fresh_module
 from test.support import threading_helper
 from http.client import HTTPException