Debugger: Remove some boiler plate in dumpers

Use Dumper.putPlainChildren where appropriate.

Change-Id: I7fc26e3b04cd67d07b2d4c7b84d5c6a8dcd6c001
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Christian Stenger <christian.stenger@digia.com>