CBQE-1107: add tests with failover to read replica tests

Change-Id: Iab7624cdb0e9602815ccef375209f1e8eb834791
Reviewed-on: http://review.couchbase.org/25392
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: buildbot <build@couchbase.com>