add test to confirm that unpacker raises errors for unknown ext type id in default
add test to confirm that unpacker raises errors for unknown ext type id in default

cosmo0920/msgpack-ruby,cosmo0920/msgpack-ruby,msgpack/msgpack-ruby,ojundt/msgpack-ruby,okkez/msgpack-ruby,okkez/msgpack-ruby,cosmo0920/msgpack-ruby,okkez/msgpack-ruby,ojundt/msgpack-ruby,msgpack/msgpack-ruby,ojundt/msgpack-ruby,ojundt/msgpack-ruby,msgpack/msgpack-ruby,okkez/msgpack-ruby,cosmo0920/msgpack-ruby