This reverts commit a97304ca03c2aeb4267dc1bd794c50aa8bdb9a69. Reason for revert: performance tests still rely in on global field trials to configure PC created by this test fixture Original change's description: > Cleanup usage of the global field trials in the PeerConnectionE2EQualityTest helper > > Bug: webrtc:42220378 > Change-Id: I3dc1a71c043ef506b6d592673b04e49f4a022d17 > Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/374901 > Reviewed-by: Jeremy Leconte <jleconte@webrtc.org> > Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> > Cr-Commit-Position: refs/heads/main@{#43803} Bug: webrtc:42220378, webrtc:392672060 Change-Id: Ide265c1284f9d53c0b652ed5e144dfb0a532f87a Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/375621 Reviewed-by: Artem Titov <titovartem@webrtc.org> Auto-Submit: Danil Chapovalov <danilchap@webrtc.org> Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com> Commit-Queue: Artem Titov <titovartem@webrtc.org> Commit-Queue: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com> Cr-Commit-Position: refs/heads/main@{#43812}