bpo-40275: Use new test.support helper submodules in tests (GH-20849)

diff --git a/Lib/test/test__xxsubinterpreters.py b/Lib/test/test__xxsubinterpreters.py
index eab8f9f..cf34fc3 100644
--- a/Lib/test/test__xxsubinterpreters.py
+++ b/Lib/test/test__xxsubinterpreters.py
@@ -10,10 +10,11 @@
 import unittest
 
 from test import support
+from test.support import import_helper
 from test.support import script_helper
 
 
-interpreters = support.import_module('_xxsubinterpreters')
+interpreters = import_helper.import_module('_xxsubinterpreters')
 
 
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