push_notifications: Provide a stable ordering.

Otherwise, this can cause test failures based on internals of the database.

zerver/tests/test_push_notifications.py

@@ -726,7 +726,7 @@ class PushBouncerNotificationTest(BouncerTestCase):
         )
         android_push.assert_called_once_with(
             user_identity,
-            list(reversed(uuid_android_tokens)),
+            uuid_android_tokens,
             {"event": "remove", "zulip_message_ids": ",".join(str(i) for i in range(50, 250))},
             {},
             remote=server,

zilencer/views.py

@@ -568,7 +568,7 @@ def remote_server_notify_push(
             user_identity.filter_q(),
             kind=RemotePushDeviceToken.GCM,
             server=server,
-        )
+        ).order_by("id")
     )
     if android_devices and user_id is not None and user_uuid is not None:
         android_devices = delete_duplicate_registrations(
@@ -580,7 +580,7 @@ def remote_server_notify_push(
             user_identity.filter_q(),
             kind=RemotePushDeviceToken.APNS,
             server=server,
-        )
+        ).order_by("id")
     )
     if apple_devices and user_id is not None and user_uuid is not None:
         apple_devices = delete_duplicate_registrations(apple_devices, server.id, user_id, user_uuid)