Autobahn test needs updating

[Dreamsorcerer]

The _make_handler() method was removed in this PR: #3939

But, is still used at: https://github.com/aio-libs/aiohttp/blob/master/tests/autobahn/server.py#L37

This needs updating, if anybody would like to take on this small task.

References to aiohttp.ws_connect() appear to also need updating:
https://github.com/aio-libs/aiohttp/blob/master/tests/autobahn/client.py#L9

[wfatherley]

For the server.py bugfix, is it sufficient to utilize web.run_app in conjunction with an on-shutdown signal, like so:

...

async def on_shutdown(app):
    for ws in set(app["websockets"]):
        await ws.close(code=WSCloseCode.GOING_AWAY, message="Server shutdown")


if __name__ == "__main__":
    logging.basicConfig(
        level=logging.DEBUG, format="%(asctime)s %(levelname)s %(message)s"
    )

    app = web.Application()
    app.router.add_route("GET", "/", wshandler)
    app.on_shutdown.append(on_shutdown)
    try:
        web.run_app(app)
    except KeyboardInterrupt:
        print("Server stopped at http://127.0.0.1:9001")

or will usage of an AppRunner be preferred?

[Dreamsorcerer]

At a quick glance, that looks good to me. Atleast, it makes more sense to me than the original code does.