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_univnewlines.py b/Lib/test/test_univnewlines.py
index 8d89936..a6c079b 100644
--- a/Lib/test/test_univnewlines.py
+++ b/Lib/test/test_univnewlines.py
@@ -111,11 +111,13 @@
 
 
 def test_main():
-    test_support.run_unittest(TestNativeNewlines)
-    test_support.run_unittest(TestCRNewlines)
-    test_support.run_unittest(TestLFNewlines)
-    test_support.run_unittest(TestCRLFNewlines)
-    test_support.run_unittest(TestMixedNewlines)
+    test_support.run_unittest(
+        TestNativeNewlines,
+        TestCRNewlines,
+        TestLFNewlines,
+        TestCRLFNewlines,
+        TestMixedNewlines
+     )
 
 if __name__ == '__main__':
     test_main()