[JBMAR-160] : SimpleMarshallerTests.testConcurrentHashMap fails on Java 8

The ConcurrentHashMap class has been changed in JDK8.
The fields segments, segmentMask and segmentShift are part of serialPersistentFields.
Solution : Consumption of empty-field stream data in the SerialUnmarshalling, the same way it is done with the RiverUnmarshaller.

[BZ 1074546] : https://bugzilla.redhat.com/show_bug.cgi?id=1074546

This is done in order to be accessible from the inner class PutField() and in the same time not being final, because then it should be initialized outside the [if (state == State.NEW)] statement.