Stop using TEST_F; that will make it easier to switch to parametric tests that are needed to correctly test `AgcManagerDirect`. "Avoid fixtures where reasonable." Source: https://abseil.io/tips/122 Bug: chromium:1275566 Change-Id: I2d73a0913eb2349144f63bd17ab4d6efa245e472 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/268766 Reviewed-by: Hanna Silen <silen@webrtc.org> Commit-Queue: Alessio Bazzica <alessiob@webrtc.org> Cr-Commit-Position: refs/heads/main@{#37556}