Issue #9517: Move script_helper to the support package.

Patch by Christie Wilson.
diff --git a/Lib/test/test_warnings.py b/Lib/test/test_warnings.py
index bda1046..c7d2e5c 100644
--- a/Lib/test/test_warnings.py
+++ b/Lib/test/test_warnings.py
@@ -5,7 +5,7 @@
 import sys
 import unittest
 from test import support
-from test.script_helper import assert_python_ok, assert_python_failure
+from test.support.script_helper import assert_python_ok, assert_python_failure
 
 from test import warning_tests