Capture/Replay: Move trace fixture into util/ This will allow us to cleanly import the fixture headers outside of libANGLE. We'll need to call into the trace fixture in the trace interpreter, which will be in util/. Bug: angleproject:7752 Change-Id: I3438989db8482924272c69e78d7ac5702e510648 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3963363 Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>