Test fixes for Python 3 (#3647)

changelog.d/3647.misc

tests/handlers/test_typing.py

tests/rest/client/test_transactions.py

tests/rest/client/v1/test_admin.py

tests/rest/client/v1/test_profile.py

tests/rest/client/v1/utils.py

tests/rest/client/v2_alpha/test_filter.py

tests/rest/client/v2_alpha/test_register.py

tests/rest/client/v2_alpha/test_sync.py

tests/server.py

tests/storage/test_event_federation.py

tests/storage/test_state.py

tests/test_server.py

tests/utils.py