Fix Flaky MockDAOTest

[HildoYe]

Have you read the docs first?
Yes

OK, describe you changes:
The test com.erudika.para.persistence.MockDAOTest#testReadPage is Flaky. It is failing when run several times with different initial random seeds. The root cause is when reading DAO to pages it assumes the MAPS is ordered while it is not.
The ConcurrentHashMap class does not guarantee the order of map when accessing it each time. This solution is to sort the Map before working on order dependent jobs.

Tests?
The test I use is mvn -pl para-server edu.illinois:nondex-maven-plugin:1.1.2:nondex -Dtest=com.erudika.para.persistence.MockDAOTest#testReadPage. You can also specify the number of runs with -DnondexRuns=NUMBER

[albogdano]

Thanks a lot for the fix!