The $out stage currently checks the viewless timeseries feature flag to decide how to run the $out aggregation over time series collection. This is a temporary solution, and we will need a solution that doesn't depend on the feature flag to support concurrent upgrade/downgrade (SERVER-112816).

SERVER-111452 marked the viewless timeseries feature flag as check_against: operation_fcv_only, which caused issues precisely because $out does not support the concurrent upgrade/downgrade. However to keep existing coverage where $out works under the assumption that the flag is stable, we implemented a workaround by acquiring and shortly releasing a FixedOperationFCVRegion.

This workaround has the unintended consequence of marking the OperationContext as interruptible - which extends even after the FixedOperationFCVRegion is released. This causes test failures in out_primary_stepdown_during_insert.js.

Provide a more targeted workaround that avoids this.