bpo-40275: Use new test.support helper submodules in tests (GH-21314)

diff --git a/Lib/test/test_capi.py b/Lib/test/test_capi.py
index 3e7afd5..55027c9 100644
--- a/Lib/test/test_capi.py
+++ b/Lib/test/test_capi.py
@@ -17,6 +17,7 @@
 import importlib.util
 from test import support
 from test.support import MISSING_C_DOCSTRINGS
+from test.support import import_helper
 from test.support import threading_helper
 from test.support.script_helper import assert_python_failure, assert_python_ok
 try:
@@ -25,7 +26,7 @@
     _posixsubprocess = None
 
 # Skip this test if the _testcapi module isn't available.
-_testcapi = support.import_module('_testcapi')
+_testcapi = import_helper.import_module('_testcapi')
 
 import _testinternalcapi