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_bisect.py b/Lib/test/test_bisect.py
index f30114d..549978d 100644
--- a/Lib/test/test_bisect.py
+++ b/Lib/test/test_bisect.py
@@ -198,8 +198,7 @@
 
 def test_main(verbose=None):
     from test import test_bisect
-    test_support.run_classtests(TestBisect,
-                                TestInsort)
+    test_support.run_unittest(TestBisect, TestInsort)
     test_support.run_doctest(test_bisect, verbose)
 
 if __name__ == "__main__":