message: Add voip_unittests to gn_isolate_map.pyl
  Adding gn isolate configs for //:voip_unittests in order to run it on
  bots.
  Cr-Commit-Position: refs/heads/master@{#30993}
diff: "label": "//:video_engine_tests",
  "type": "console_test_launcher",
  },
  + "voip_unittests": {
  + "label": "//:voip_unittests",
  + "type": "console_test_launcher",
  + },
  "webrtc_nonparallel_tests": {
  "label": "//:webrtc_nonparallel_tests",
  "type": "non_parallel_console_test_launcher",
  