CDRIVER-4275 and CDRIVER-4275 (#1158)

* set loadBalanced=true in URI if testing with load balancer

* Update integration-tests.sh and orchestration configs

* add LOAD_BALANCER to 'bootstrap mongo-orchestration' function

* use /tmp/orchestration-home path

This matches expectation of integration-tests.sh.

* remove mongoc_global_mock_service_id

This was only needed when MongoDB servers did not return a serviceId in the hello response.

* update loadBalanced DNS tests

Tests were updated in mongodb/specifications commit: 5d1b42a05017ba27ffdbe6fd068a45e93e5b68c5