For some reasons when we delete a MergeTree Part in atomic way something may go wrong - and leave the `delete_tmp_*` folder or it's part on disk. This may lead to a disk space consumption over time.

It's suggested to delete this folders at least at server start-up. Current solution with `clearOldTemporaryDirectories()` doesn't work because this method is called periodically from a thread without any locks or advisory on folders - it may cause the race conditions.
return;
    try
    {
        background_operations_assignee.start();
        startBackgroundMovesIfNeeded();
    }
    catch (...)
    {
        
        
        
        try
        {
            shutdown();
        }
        catch (...)
        {
            std::terminate();
        }
        
        throw;
    }
}
void StorageMergeTree::flush()
{
    if (flush_called.exchange(true))
        return;
    flushAllInMemoryPartsIfNeeded();
}
void StorageMergeTree::shutdown()