[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

You can't have an invariant on PutField that it can only be called once.

java version "1.8.0_25"
Java(TM) SE Runtime Environment (build 1.8.0_25-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.25-b02, mixed mode)
ConcurrentHashMap
```
        s.putFields().put("segments", segments);
        s.putFields().put("segmentShift", segmentShift);
        s.putFields().put("segmentMask", segmentMask);
        s.writeFields();
```