Increase dynamicBoost and dynamicBoostLite full-text test coverage

dynamicBoost and dynamicBoostLite have limited full-text capabilities. The Elastic implementation of dynamicBoost offers some full text capability without affecting the index size

In general, this feature has a good test coverage for the indexing part but very basic tests around the queries. The reason of this is that in Lucene the query logic is not part of oak but it resides in an external component not owned by the indexing team.

The goal of this task is to:

1) improve unit tests for dynamicBoostLite (this can be done for all index types)

2) improve full-text unit tests for dynamicBoost in Elastic. Compared to Lucene, we have more flexibility since there are no dependencies with external code.

Once 1 is implemented, we can potentially improve full-text support for dynamicBoostLite using more sophisticated queries (currently a simple Term query is used).