FR: `cfn test` to log contract name in rpdk.log

Hello team,

I'd be very useful to add in the logging of the rpdk.log file which contract test is running when the request is sent / received.
If you are running tests it becomes very difficult to track which payload was sent and map it back to the contract unless you tediously "count" each pair of request/response.

That'd help a lot in troubleshooting.

Thank you :)