CDRIVER-4717 sync legacy transaction tests for LB runOnRequirements (#1507)

Synced with mongodb/specifications@38e65fc8e59fedea351d9393ae43d305cde6ce00

This includes error-labels-blockConnection.json for client-side operations timeout, which is not yet implemented in libmongoc.

Per run-tests.sh, these tests will not actually be executed on load balancers. This is intentional to avoid making further changes to the legacy spec test runner to support LBs.

* Add trailing newline to skipped test output