
**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)

{
                found = true;
                break;
            }
        }
        if (!found)
        {
            for (const auto & col : metadata_snapshot->getColumns().getMaterialized())
            {
                if (col.name == column_name)
                    throw Exception("Cannot UPDATE materialized column " + backQuote(column_name), ErrorCodes::CANNOT_UPDATE_COLUMN);
            }
            throw Exception("There is no column " + backQuote(column_name) + " in table", ErrorCodes::NO_SUCH_COLUMN_IN_TABLE);
        }
        if (key_columns.count(column_name))
            throw Exception("Cannot UPDATE key column " + backQuote(column_name), ErrorCodes::CANNOT_UPDATE_COLUMN);
        auto materialized_it = column_to_affected_materialized.find(column_name);
        if (materialized_it != column_to_affected_materialized.end())
        {
            for (const String & materialized : materialized_it->second)
            {
                if (key_columns.count(materialized))
                    throw Exception("Updated column " + backQuote(column_name) + " affects MATERIALIZED column "
                        + backQuote(materialized) + ", which is a key column. Cannot UPDATE it.",
                        ErrorCodes::CANNOT_UPDATE_COLUMN);
            }
        }
    }
}
ASTPtr MutationsInterpreter::prepare(bool dry_run)