Issue #21741: Update 147 test modules to use test discovery.

I have compared output between pre- and post-patch runs of these tests
to make sure there's nothing missing and nothing broken, on both
Windows and Linux.  The only differences I found were actually tests
that were previously *not* run.

1 files changed, 1 insertions, 5 deletions

diff --git a/Lib/test/test_defaultdict.py b/Lib/test/test_defaultdict.py
index 48d1cb5..a90bc2b 100644
--- a/Lib/test/test_defaultdict.py
+++ b/Lib/test/test_defaultdict.py
@@ -5,7 +5,6 @@ import copy
 import pickle
 import tempfile
 import unittest
-from test import support
 
 from collections import defaultdict
 
@@ -184,8 +183,5 @@ class TestDefaultDict(unittest.TestCase):
             o = pickle.loads(s)
             self.assertEqual(d, o)
 
-def test_main():
-    support.run_unittest(TestDefaultDict)
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()