Some tests did not pass on repeated calls (regrtest -R::)
Perform additional cleanup, mostly deleting from sys.modules, or clearing the warnings registry.
diff --git a/Lib/test/test_frozen.py b/Lib/test/test_frozen.py
index e981fb3..4835e47 100644
--- a/Lib/test/test_frozen.py
+++ b/Lib/test/test_frozen.py
@@ -35,6 +35,10 @@
         self.assertEquals(stdout.getvalue(),
                           'Hello world...\nHello world...\nHello world...\n')
 
+        del sys.modules['__hello__']
+        del sys.modules['__phello__']
+        del sys.modules['__phello__.spam']
+
 
 def test_main():
     run_unittest(FrozenTests)