In SERVER-90798 we made the CSR/DSS locks uninterruptible by using a shared_mutex. With this change we lose the coverage of the deadlock detector that SERVER-99150 introduced, so it would be good to use a proper Lock that's part of the hierarchy and can be checked by the detector.

We don't want to incentivize other engineers to use this uninterruptible lock, we only want it for testing, so the proposal is to make sure it's only available in debug mode, and in production make the CSR/DSS use a shared_mutex under the hood.