asyncio: Synchronize with Tulip

* Issue #159: Fix windows_utils.socketpair()

  - Use "127.0.0.1" (IPv4) or "::1" (IPv6) host instead of "localhost", because
    "localhost" may be a different IP address
  - Reject also invalid arguments: only AF_INET/AF_INET6 with SOCK_STREAM (and
    proto=0) are supported

* Reject add/remove reader/writer when event loop is closed.
* Fix ResourceWarning warnings

Lib/test/test_asyncio/test_events.py

@@ -1326,6 +1326,30 @@ class EventLoopTestsMixin:
                     self.assertIn('address must be resolved',
                                   str(cm.exception))
 
+    def test_remove_fds_after_closing(self):
+        loop = self.create_event_loop()
+        callback = lambda: None
+        r, w = test_utils.socketpair()
+        self.addCleanup(r.close)
+        self.addCleanup(w.close)
+        loop.add_reader(r, callback)
+        loop.add_writer(w, callback)
+        loop.close()
+        self.assertFalse(loop.remove_reader(r))
+        self.assertFalse(loop.remove_writer(w))
+
+    def test_add_fds_after_closing(self):
+        loop = self.create_event_loop()
+        callback = lambda: None
+        r, w = test_utils.socketpair()
+        self.addCleanup(r.close)
+        self.addCleanup(w.close)
+        loop.close()
+        with self.assertRaises(RuntimeError):
+            loop.add_reader(r, callback)
+        with self.assertRaises(RuntimeError):
+            loop.add_writer(w, callback)
+
 
 class SubprocessTestsMixin:
 
@@ -1632,6 +1656,9 @@ if sys.platform == 'win32':
         def test_create_datagram_endpoint(self):
             raise unittest.SkipTest(
                 "IocpEventLoop does not have create_datagram_endpoint()")
+
+        def test_remove_fds_after_closing(self):
+            raise unittest.SkipTest("IocpEventLoop does not have add_reader()")
 else:
     from asyncio import selectors