Re-enabled multithreaded encoding using OpenH264, as the issue described in crbug.com/583348 no longer applies. Bug: webrtc:14368 Change-Id: I5ae768a6edf3b40d99c13fb4ee4662626c993a66 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/271820 Reviewed-by: Sergey Silkin <ssilkin@webrtc.org> Commit-Queue: Sergey Silkin <ssilkin@webrtc.org> Cr-Commit-Position: refs/heads/main@{#37837}