'checkout_angle_restricted_traces' controls if we should check out
the trace tests. We can give restricted access to partners for these
traces. Defaults to the same setting as 'checkout_angle_internal'.

Bug: angleproject:5860
Change-Id: I36efffb180b35e11e104e2c99bc89fb4be4e0708
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2822232Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>