CTest: Weight reported test times by PROCESSORS in summaries

This commit changes the times reported by labels and sub projects to be weighted by the PROCESSORS property. This gives a more accurate idea of how much compute time sub projects and labels are taking. This commit also splits out the reporting of labels and labels used for sub projects. If a label is a sub project label it will not be included in the label summary. Finnally, this commit creates PrintLabelOrSubprojectSummary which is able to do the work of both PrintLabelSummary and PrintSubprojectSummary avoiding code duplication.