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.
{
    {
        std::lock_guard lock(existing_nodes_cache_mutex);
        if (existing_nodes_cache.contains(path))
            return true;
    }
    bool res = getZooKeeper()->exists(path);
    if (res)
    {
        std::lock_guard lock(existing_nodes_cache_mutex);
        existing_nodes_cache.insert(path);
    }
    return res;
}
std::optional<EphemeralLockInZooKeeper>