Issue #9517: Move script_helper to the support package.

Patch by Christie Wilson.
diff --git a/Lib/test/test_capi.py b/Lib/test/test_capi.py
index 367feaa..eae3add 100644
--- a/Lib/test/test_capi.py
+++ b/Lib/test/test_capi.py
@@ -11,7 +11,7 @@
 import unittest
 from test import support
 from test.support import MISSING_C_DOCSTRINGS
-from test.script_helper import assert_python_failure
+from test.support.script_helper import assert_python_failure
 try:
     import _posixsubprocess
 except ImportError: