merge_pr_46318

Remove experimental sync-script policy.

This document policy (previously feature policy) has been in an
experimental state for several years, and there are no current plans to
ship it. Removing the feature to reduce the maintenance burden of unused
code.

Bug: 340920459
Change-Id: I26010c6d4f934bd764be3d4166d75a91987c823a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5544698
Reviewed-by: Rick Byers rbyers@chromium.org
Reviewed-by: Ken Buchanan kenrb@chromium.org
Commit-Queue: Ian Clelland iclelland@chromium.org
Cr-Commit-Position: refs/heads/main@{#1302964}