Issue #21038: Cleanup test_epoll.py

Remove useless test and unused variables. Initial patch by Andreas Schwab.

Lib/test/test_epoll.py

@@ -174,11 +174,8 @@ class TestEPoll(unittest.TestCase):
         expected.sort()
 
         self.assertEqual(events, expected)
-        self.assertFalse(then - now > 0.01, then - now)
 
-        now = time.time()
         events = ep.poll(timeout=2.1, maxevents=4)
-        then = time.time()
         self.assertFalse(events)
 
         client.send(b"Hello!")