Fixed flaky test-case testBeanToListGeneration() in class BeanToListGenerationTestCase

[hermya]

This fix is similar to a previous PR : #403
POINT OF FAILURE -> random attribute ordering produced by factory.classMap(Clazz, Clazz) When field(fromClassField, toClassField) is not called for all hierarchical attributes, the one left out will appear in random order.

Example:

{
"a" : 1,
"b" : {
   "c": 2,
   "d": 3
}
}

and when --""--.field("b.c", "0") is called, (converting obj to List<Object>)

the mapped destination List<Object> could be: [2, 1, 3] OR [2, 3, 1]

---

Possible fix: for all unmapped attrs, use lexographical ordering or throw exception

Fixed using NonDex, plugin added in parent pom.
Suggested command to check flaky tests :

mvn nondex:nondex

For particular test:

mvn -pl ./core edu.illinois:nondex-maven-plugin:2.1.7:nondex -Dtest=ma.glasnost.orika.test.generator.BeanToListGenerationTestCase#testBeanToListGeneration -DnondexRuns=10 -Dmode=ONE

For more information : https://github.com/TestingResearchIllinois/NonDex