Instead, serialize to CBOR, then convert to JSON.
I plan to remove the JSON serialization support from
protocol::Value and from the generated types. We're
close - three files here, four files in Chromium.

Change-Id: I067dc896dad1bb7cd95914b3dcc86597f136251b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2008751
Commit-Queue: Johannes Henkel <johannes@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65909}