bpo-41521: Rename blacklist parameter to not_exported (GH-21824)

Rename "blacklist" parameter of test.support.check__all__() to
"not_exported".
diff --git a/Lib/test/test_wave.py b/Lib/test/test_wave.py
index eb231cb..f85e40b 100644
--- a/Lib/test/test_wave.py
+++ b/Lib/test/test_wave.py
@@ -107,8 +107,7 @@
 
 class MiscTestCase(unittest.TestCase):
     def test__all__(self):
-        blacklist = {'WAVE_FORMAT_PCM'}
-        support.check__all__(self, wave, blacklist=blacklist)
+        support.check__all__(self, wave, not_exported={'WAVE_FORMAT_PCM'})
 
 
 class WaveLowLevelTest(unittest.TestCase):