Build dashboard contains stale reports

The build dashboard task currently does not link reports that were generated by the current gradle execution only, but also stale reports from former invocations. If this is really the expected behaviour, it would at least be nice to mark them in the build dashboard as probably stale. Currently if you execute the tests for some subproject1, then update from remote repository with many changes in that subproject and then execute tests for subproject2, the build dashboard will still link reports of both runs and it is not too clear that you may have obsolete information linked to look at.