asyncio: sync with Tulip

* PipeHandle now uses None instead of -1 for a closed handle
* Sort imports in windows_utils.
* Fix test_events on Python older than 3.5. Skip SSL tests on the
  ProactorEventLoop if ssl.MemoryIO is missing
* Fix BaseEventLoop._create_connection_transport(). Close the transport if the
  creation of the transport (if the waiter) gets an exception.
* _ProactorBasePipeTransport now sets _sock to None when the transport is
  closed.
* Fix BaseSubprocessTransport.close(). Ignore pipes for which the protocol is
  not set yet (still equal to None).
* TestLoop.close() now calls the close() method of the parent class
  (BaseEventLoop).
* Cleanup BaseSelectorEventLoop: create the protocol on a separated line for
  readability and ease debugging.
* Fix BaseSubprocessTransport._kill_wait(). Set the _returncode attribute, so
  close() doesn't try to terminate the process.
* Tests: explicitly close event loops and transports
* UNIX pipe transports: add closed/closing in repr(). Add "closed" or "closing"
  state in the __repr__() method of _UnixReadPipeTransport and
  _UnixWritePipeTransport classes.

Lib/asyncio/selector_events.py

@@ -182,13 +182,14 @@ class BaseSelectorEventLoop(base_events.BaseEventLoop):
             else:
                 raise  # The event loop will catch, log and ignore it.
         else:
+            protocol = protocol_factory()
             if sslcontext:
                 self._make_ssl_transport(
-                    conn, protocol_factory(), sslcontext,
+                    conn, protocol, sslcontext,
                     server_side=True, extra={'peername': addr}, server=server)
             else:
                 self._make_socket_transport(
-                    conn, protocol_factory(), extra={'peername': addr},
+                    conn, protocol , extra={'peername': addr},
                     server=server)
         # It's now up to the protocol to handle the connection.