private final HitGroup addHits(int count,String idPrefix,HitGroup to) {
        for (int i=1; i<=count; i++)
            to.add(new Hit(idPrefix + i,1/i));
        return to;
    }
Tests the speed of accessing hits in the query by id

@author bratseth
container-search/src/test/java/com/yahoo/search/test/ResultBenchmark.java