Issue #21119: asyncio now closes sockets on errors

Fix ResourceWarning: create_connection(), create_datagram_endpoint() and
create_unix_server() methods of event loop now close the newly created socket
on error.

Lib/asyncio/unix_events.py

@@ -223,6 +223,9 @@ class _UnixSelectorEventLoop(selector_events.BaseSelectorEventLoop):
                     raise OSError(errno.EADDRINUSE, msg) from None
                 else:
                     raise
+            except:
+                sock.close()
+                raise
         else:
             if sock is None:
                 raise ValueError(