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_xpickle.py b/Lib/test/test_xpickle.py
index cc458ad..42cd0f4 100644
--- a/Lib/test/test_xpickle.py
+++ b/Lib/test/test_xpickle.py
@@ -35,12 +35,10 @@
         return cPickle.loads(buf)
 
 def test_main():
-    suite = unittest.TestSuite()
-    for test in (DumpCPickle_LoadPickle,
-                 DumpPickle_LoadCPickle,
-                ):
-        suite.addTest(unittest.makeSuite(test))
-    test_support.run_suite(suite)
+    test_support.run_unittest(
+        DumpCPickle_LoadPickle,
+        DumpPickle_LoadCPickle
+    )
 
 if __name__ == "__main__":
     test_main()