Support syncing traces to experimental CIPD prefix. This lets us test a retrace without first committing it to the immutable "angle" prefix. Bug: angleproject:5133 Change-Id: Ia52ccffe69faf099d6fc92eaf392610eefa549f1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3118270 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Tim Van Patten <timvp@google.com>