Remove traces of MacOS9 support.

Fix for issue #7908
diff --git a/Lib/test/test_select.py b/Lib/test/test_select.py
index 8813c6e..fe92f45 100644
--- a/Lib/test/test_select.py
+++ b/Lib/test/test_select.py
@@ -4,7 +4,7 @@
 import os
 import sys
 
-@unittest.skipIf(sys.platform[:3] in ('win', 'mac', 'os2', 'riscos'),
+@unittest.skipIf(sys.platform[:3] in ('win', 'os2', 'riscos'),
                  "can't easily test on this system")
 class SelectTestCase(unittest.TestCase):