hi,
v21.12.3.1-stable
clickhouse-client execute 'system RELOAD FUNCTION on cluster cluster test_function;'
Actual execution differs from expectations.

![image](https://user-images.githubusercontent.com/35019926/153533788-53ed9c1f-d383-4bc8-b85e-d1828328ad7e.png)



{
    if (database)
    {
        std::erase(children, database);
        database.reset();
    }
    if (!name.empty())
    {
        database = std::make_shared<ASTIdentifier>(name);
        children.push_back(database);
    }
}
void ASTSystemQuery::setTable(const String & name)
{
    if (table)
    {
        std::erase(children, table);
        table.reset();
    }
    if (!name.empty())
    {
        table = std::make_shared<ASTIdentifier>(name);
        children.push_back(table);
    }
}
void ASTSystemQuery::formatImpl(const FormatSettings & settings, FormatState &, FormatStateStacked) const