jstests/sharding/csrs_upgrade_during_migrate.js
jstests/sharding/csrs_upgrade.js

These tests are currently excluded from the sharding_continuous_config_stepdown suite because sharding_continuous_config_stepdown.js does not handle SYNC config servers: it just throws an error "Continuous config server step down only available with CSRS." However, these tests upgrade to CSRS, which we want to test with continuous failover.

Make modifications so these tests can be run in the failover suite. *A starting idea: if the test has SYNC config servers, skip starting the continuous failover thread, and start it when the upgrade occurs.