asyncio: Add close() back to Unix selector event loop, to remove all signal handlers. Should fix buildbot issues.
diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py
index dd57fe8..f4cf6e7 100644
--- a/Lib/asyncio/unix_events.py
+++ b/Lib/asyncio/unix_events.py
@@ -48,6 +48,11 @@
     def _socketpair(self):
         return socket.socketpair()
 
+    def close(self):
+        for sig in list(self._signal_handlers):
+            self.remove_signal_handler(sig)
+        super().close()
+
     def add_signal_handler(self, sig, callback, *args):
         """Add a handler for a signal.  UNIX only.