Also parameterized tests to test the new generic descriptor and added --generic_descriptor flag to loopback tests. Bug: webrtc:9361 Change-Id: I2b76889606fe2e81249ecdebb0b7b61151682485 Reviewed-on: https://webrtc-review.googlesource.com/101900 Commit-Queue: Philip Eliasson <philipel@webrtc.org> Reviewed-by: Erik Språng <sprang@webrtc.org> Reviewed-by: Danil Chapovalov <danilchap@webrtc.org> Reviewed-by: Stefan Holmer <stefan@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24835}