RDF-2020 Calibration Testcases

This version is matched with the RDF-2020 paper,

J. Chen, I. H.-R. Jiang, J. Jung, A. B. Kahng, V. N. Kravets, Y.-L. Li, S.-T. Lin and M. Woo, "DATC RDF-2020: Strengthening the Foundation for Academic Research in IC Physical Design", Proc. IEEE/ACM International Conference on Computer-Aided Design (ICCAD), 2020. (Invited)