[C++] ArbitratorTest uses shared_ptr for Arbitrator instances
[C++] ArbitratorTest uses shared_ptr for Arbitrator instances

Change-Id: I13e73cd61ac08055eb0cb7315722e92b01807e93

bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr