FLEDGE: basic WPT for hybrid B&A auctions.
...where a B&A auction is a component in a client-side auction.
(And also remove some unused fields from pure B&A ones)
Change-Id: Ic8e14a087d432af0a0f93880ed2c2278f74069cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5858038
Reviewed-by: Russ Hamilton behamilton@google.com
Commit-Queue: Maks Orlovich morlovich@chromium.org
Cr-Commit-Position: refs/heads/main@{#1354798}