Prior to SERVER-66690, it was sufficient to clear a deleted bucket from the BucketCatalog via the OpObserver's aboutToDelete method. With reopening, it became necessary to clear it from onDelete, which does not have access to the bucket's ID unless we record preimages in the oplog. Since this can have a performance impact, we want to avoid this, and since we don't need the full preimage, just the ID, we can probably stash the IDs on the OperationContext.