Combine the functionality of test_support.run_unittest()
and test_support.run_classtests() into run_unittest()
and use it wherever possible.

Also don't use "from test.test_support import ...", but
"from test import test_support" in a few spots.

From SF patch #662807.
diff --git a/Lib/test/test_shutil.py b/Lib/test/test_shutil.py
index cd2469a..3a39ec9 100644
--- a/Lib/test/test_shutil.py
+++ b/Lib/test/test_shutil.py
@@ -14,15 +14,9 @@
 
 
 
-def suite():
-    suite = unittest.TestSuite()
-    suite.addTest(unittest.makeSuite(TestShutil))
-    return suite
-
-
 def test_main():
-    test_support.run_suite(suite())
+    test_support.run_unittest(TestShutil)
 
 
 if __name__ == '__main__':
-    unittest.main(defaultTest='suite')
+    test_main()