@Override
    public Object get(CompoundName name, Map<String,String> context,
                      com.yahoo.processing.request.Properties substitution) {
        return super.get(name, context == null ? this.context : context, substitution);
    }
Turns get(name) into get(name, context) using the request given at construction time
and the zone info.
This is used to allow the query's request to be supplied to all property requests
without forcing users of the query.properties() to supply this explicitly.

@author bratseth
container-search/src/main/java/com/yahoo/search/query/properties/RequestContextProperties.java