Clean up json-based test coverage from misc policy tests

The feature has been launched by default in Q1, this CL cleans up its
references in preparaion for the final deletion.

Bug: b:478929452
Change-Id: I396deb0864f8f39a72609c456a1c73fb19ff8127
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/8019808
Commit-Queue: Nancy Xiao <nancylanxiao@google.com>
Reviewed-by: Pavol Marko <pmarko@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1654413}
NOKEYCHECK=True
GitOrigin-RevId: 4a01dff49c024b2faa500a851496747347f479ae