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_enumerate.py b/Lib/test/test_enumerate.py
index 1fa9479..701b0c0 100644
--- a/Lib/test/test_enumerate.py
+++ b/Lib/test/test_enumerate.py
@@ -104,14 +104,8 @@
 
     enum = MyEnum
 
-def suite():
-    suite = unittest.TestSuite()
-    suite.addTest(unittest.makeSuite(EnumerateTestCase))
-    suite.addTest(unittest.makeSuite(SubclassTestCase))
-    return suite
-
 def test_main():
-    test_support.run_suite(suite())
+    test_support.run_unittest(EnumerateTestCase, SubclassTestCase)
 
 if __name__ == "__main__":
     test_main()