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_tempfile.py b/Lib/test/test_tempfile.py
index 09b9a10..8df3856 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -645,10 +645,7 @@
     test_classes.append(test_TemporaryFile)
 
 def test_main():
-    suite = unittest.TestSuite()
-    for c in test_classes:
-        suite.addTest(unittest.makeSuite(c))
-    test_support.run_suite(suite)
+    test_support.run_unittest(*test_classes)
 
 if __name__ == "__main__":
     test_main()