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.

Lib/test/test_unicodedata.py

@@ -313,12 +313,5 @@ class UnicodeMiscTest(UnicodeDatabaseTest):
                 self.assertEqual(len(lines), 1,
                                  r"\u%.4x should not be a linebreak" % i)
 
-def test_main():
-    test.support.run_unittest(
-        UnicodeMiscTest,
-        UnicodeMethodsTest,
-        UnicodeFunctionsTest
-    )
-
 if __name__ == "__main__":
-    test_main()
+    unittest.main()