
**Bug description**
Unlike `cluster()`, `clusterAllReplicas()` does not implement `_shard_num`. 

I would expect
```
SELECT _shard_num
FROM clusterAllReplicas(prod, system.one)
ORDER BY _shard_num ASC
FORMAT PrettyCompactMonoBlock

┌─_shard_num─┐
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
│          0 │
└────────────┘
```
to have an output more useful like
```
SELECT _shard_num
FROM cluster(prod, system.one)
ORDER BY _shard_num ASC
FORMAT PrettyCompactMonoBlock

┌─_shard_num─┐
│          1 │
│          2 │
│          3 │
│          4 │
│          5 │
│          6 │
│          7 │
│          8 │
│          9 │
│         10 │
│         11 │
│         12 │
│         13 │
│         14 │
│         15 │
└────────────┘
```

**Releases where this has been tested**

* v20.3.12.112-stable

**References**

[cluster, clusterAllReplicas documentation](https://clickhouse.tech/docs/en/sql-reference/table-functions/cluster/)

[_shard_num documentation](https://clickhouse.tech/docs/en/engines/table-engines/special/distributed/#virtual-columns)

if (startsWith(replica_key, "replica"))
                {
                    replica_addresses.emplace_back(config,
                        partial_prefix + replica_key,
                        cluster_name,
                        secret,
                        current_shard_num,
                        current_replica_num);
                    ++current_replica_num;
                    if (internal_replication)
                    {
                        
                        {
                            auto dir_name = replica_addresses.back().toFullString(false );
                            if (!replica_addresses.back().is_local)
                                concatInsertPath(insert_paths.prefer_localhost_replica, dir_name);
                            concatInsertPath(insert_paths.no_prefer_localhost_replica, dir_name);
                        }
                        
                        {
                            auto dir_name = replica_addresses.back().toFullString(true );
                            if (!replica_addresses.back().is_local)
                                concatInsertPath(insert_paths.prefer_localhost_replica_compact, dir_name);
                            concatInsertPath(insert_paths.no_prefer_localhost_replica_compact, dir_name);
                        }
                    }
                }
                else
                    throw Exception("Unknown element in config: " + replica_key, ErrorCodes::UNKNOWN_ELEMENT_IN_CONFIG);
            }