Create StartOnDemandAny tests in Testnet

Create a testcase that verifies that the KeepAlive server, which is started with `StartonDemandAny` works as intended. That is the KeepAlive server starts when any warm or hot protocol starts and that it will throw a timeout exception if the KeepAlive client doesn't start within 97s.

Start by locating the Testnet code and existing tests for StartonDemandAny and the KeepAlive server, then run the relevant Testnet test suite. Done means tests cover startup when any warm or hot protocol starts and the timeout when the KeepAlive client does not start within 97 seconds.

Written by the indexing model from the issue text.