crimson/test: implement v2 failover tests with crimson FailoverTestPeer
* Test framework which is able to bring up a local FailoverSuitePeer
or connect to a remote FailoverSuitePeer;
* Implemented crimson FailoverSuitePeer;
* Test framework which can declare failure cases, messenger operations
and introspect test results for different kinds of tests ;
* 47 test cases to cover combinations of policies and faults;