Allow for make_awaitable's return value to be re-used. (#8261)

changelog.d/8261.misc

tests/federation/test_complexity.py

tests/federation/test_federation_sender.py

tests/handlers/test_auth.py

tests/handlers/test_register.py

tests/handlers/test_typing.py

tests/replication/test_federation_sender_shard.py

tests/rest/admin/test_user.py

tests/server_notices/test_resource_limits_server_notices.py

tests/storage/test_client_ips.py

tests/storage/test_monthly_active_users.py

tests/test_utils/__init__.py