[tests] Make random seed logged and settable
[tests] Make random seed logged and settable

This allows tests which use randomness to be reproducibly run on failure.


Former-commit-id: adfc646b03b1cb82e77f51df3a3b1fba843c3ff8
syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin2,syscoin/syscoin2,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin