Run RPC tests with explicitly defined datadir
Run RPC tests with explicitly defined datadir

When there is a also a configuration file in the standard datadir, using the CLI still works, but it can result in warnings like:

Error: Invalid combination of -regtest and -testnet.

OmniLayer/omnicore,OmniLayer/omnicore,OmniLayer/omnicore,OmniLayer/omnicore,OmniLayer/omnicore,OmniLayer/omnicore