Add an option for `clickhouse-client` with a list of tests for extensive fuzzing.
Processing of these tests will be interleaved between every other tests, so we will get much better fuzzing coverage.
{
        std::cout << DBMS_NAME << " client version " << VERSION_STRING << VERSION_OFFICIAL << "." << st;
    }
public:
    void init(int argc, char ** argv)
    {
        /// Don't parse options with Poco library. We need more sophisticated processing.
        stopOptionsProcessing();
        /** We allow different groups of arguments:
          * - common arguments;
          * - arguments for any number of external tables each in form "--external args...",
          *   where possible args are file, name, format, structure, types;
          * - param arguments for prepared statements.
          * Split these groups before processing.
          */
        using Arguments = std::vector<std::string>;
        Arguments common_arguments{""};        /// 0th argument is ignored.
        std::vector<Arguments>