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_calendar.py b/Lib/test/test_calendar.py
index c0b746b..f8c6d56 100644
--- a/Lib/test/test_calendar.py
+++ b/Lib/test/test_calendar.py
@@ -1,7 +1,7 @@
 import calendar
 import unittest
 
-from test.test_support import run_unittest
+from test import test_support
 
 
 class CalendarTestCase(unittest.TestCase):
@@ -55,7 +55,7 @@
             self.assertEqual(len(d), 13)
 
 def test_main():
-    run_unittest(CalendarTestCase)
+    test_support.run_unittest(CalendarTestCase)
 
 if __name__ == "__main__":
     test_main()