Improve stability of RobinEngineIntegrationTest by reducing direct memory usage of the test env
External method to set rootTypeParsers in DocumentMapperParser incorrect
fixes #4113
Set MaxDirectMemorySize for tests to have consistent upper bounds
Reduce number of documents in RobinEngineIntegrationTest to prevent memory peaks triggering OOM
Guarantee sorted order for [Double|Long|Bytes]Values

Values returned by [Double|Long|Bytes]Values are sorted today which
is guaranteed by the underlying Lucene index. Several implementations can
make use of this property but the interfaces don't guarantee this behavior.
This commit adds the guarantees and makes use of them in several places.

Note: This change might require sorting for 3rd party implemenations of these
interaces.