Add new joined_block_split_single_row

Add new joined_block_split_single_row setting to reduce memory usage in hash joins with many matches per key. This allows hash join results to be chunked even within matches for a single left table row, which is particularly useful when one row from the left table matches thousands or millions of rows from the right table. Previously, all matches had to be materialized at once in memory. This reduces peak memory usage but may increase CPU usage. #87913 (Vladimir Cherkasov).