bpo-40275: Use new test.support helper submodules in tests (GH-21448)

diff --git a/Lib/test/test_stat.py b/Lib/test/test_stat.py
index d9e4ffd..83d09e1 100644
--- a/Lib/test/test_stat.py
+++ b/Lib/test/test_stat.py
@@ -3,7 +3,9 @@
 import socket
 import sys
 from test.support import socket_helper
-from test.support import TESTFN, import_fresh_module
+from test.support.import_helper import import_fresh_module
+from test.support.os_helper import TESTFN
+
 
 c_stat = import_fresh_module('stat', fresh=['_stat'])
 py_stat = import_fresh_module('stat', blocked=['_stat'])