bpo-40275: Use new test.support helper submodules in tests (GH-20824)

diff --git a/Lib/test/test_getopt.py b/Lib/test/test_getopt.py
index 9275dc4..9261276 100644
--- a/Lib/test/test_getopt.py
+++ b/Lib/test/test_getopt.py
@@ -1,7 +1,8 @@
 # test_getopt.py
 # David Goodger <dgoodger@bigfoot.com> 2000-08-19
 
-from test.support import verbose, run_doctest, EnvironmentVarGuard
+from test.support import verbose, run_doctest
+from test.support.os_helper import EnvironmentVarGuard
 import unittest
 
 import getopt