Stress tests for the RAR task: manually add tests.

[AR-May]

We would like to implement and perform stress tests for the RAR task in order to identify possible issues with concurrency. This issue is part of the RAR as a service user story: #3139.

Some of the RAR inputs/outputs are rarely used. The goal of this issue is to:

• review the automatically-collected data set of inputs and outputs of RAR task from issue Stress tests for the RAR task: collect data set. #6296 in order to find unused ones.
• manually add some tests for missed inputs/outputs in order to get full coverage of all the possible inputs and outputs of the RAR task.