The list of commands in kCommandsSupportingReadConcern should be updated to account for how the "insert", "update", "delete", and "findAndModify" / "findandmodify" commands support readConcern={level: "snapshot"}. The aforementioned commands however do not support readConcern={level: "majority"} and should therefore continue to omit a readConcern when that is the configured TestData.defaultReadConcernLevel.