In the previous broker load, multiple OlapTableSinks would send data to the same LoadChannel,
and because of the lock granularity problem, LoadChannel could only process these requests serially,
which made it impossible to make full use of cluster resources.
This CL modifies the related locks so that LoadChannel can process these requests in parallel.
In the test, with a size of 20G, the load speed of 334 million rows of data in 3 nodes has been
increased from 9min to 5min, and after enabling 2 concurrency, it can be increased to 3min.
Also modify the profile of load job.
51ccd44865