SERVER-42299, setFeatureCompatibilityVersion uses transactions to modify sharded metadata on the config server when run in a sharded cluster. This command may be called in the validate collections hook run after a fuzzer test if the cluster does not have the expected FCV. Fuzzer suites reduce the transactionLifetimeLimitSeconds parameter to 1 second, so it's possible for validate collections to fail against sharded clusters if a setFCV transaction is killed for exceeding 1 second.
To get around this, transactionLifetimeLimitSeconds should be temporarily raised while running setFCV in validate collections. This behavior can be removed as part of SERVER-44034.