Update ArrayConverterTest.java

[yannizhou05]

The tests below were found flaky because of the ordering of HashSets and HashMaps. The orders of elements in the HashSets and HashMaps are not the same every time being called. In this case, HashSet is changed into LinkedHashSet, and the unordered results from HashMap are sorted for comparing. This code change is trying to fix the flaky tests mentioned above, because they sometimes fail (as the picture showed) and sometimes pass when comparing the strings. The failure could be reproduced by the commands above by using the tool of NonDex. The code change is to make sure the tests will always pass in this case.

• org.modelmapper.internal.converter.ArrayConverterTest.shouldConvertFromSet
• org.modelmapper.internal.TypeInfoImplTest.shouldProduceMutators
• org.modelmapper.internal.TypeInfoImplTest.shouldProduceAccessors

The test failures could be reproduced by

1. mvn install -pl . -am -DskipTests
2. run tests with NonDex
   mvn -pl core edu.illinois:nondex-maven-plugin:1.1.2:nondex -Dtest=org.modelmapper.internal.TypeInfoImplTest#shouldProduceAccessors