Introduce a server parameter shutdownTimeoutMillisForSignaledShutdown on mongod. This controls the combined time taken by stepdown and quiesce mode for SIGTERM shutdown. The default value is 15000. Set this to 100 in tests. (Check that for multi-node replica sets, this is often enough time to step down and spend time in quiesce mode.) Remove the server parameter waitForStepDownOnSignaledShutdown, so that the two timeouts are combined.