Parallel query: allow parallel scans on ranges in InnoDB clustered index

While MDEV-39491 focuses on full table scans, parallel scanning should be also available for range scans. The scope of this task is to

• enable partitioning to chunks for ranges on the InnoDB primary key (clustered index);
• let the optimizer run parallel execution for tables accessed by range;
• measure performance impact of parallelism on those scans.