Adding gn isolate configs for //:voip_unittests in order to run it on bots. Bug: webrtc:11251 Change-Id: I00636cb136db116a3b90a7aad4c55c4e4697534b Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/172804 Reviewed-by: Artem Titov <titovartem@webrtc.org> Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30993}