This will allow me to reuse the routines for the
inspector_protocol/encoding/encoding_test, rather than copy them.
I've already verified that this works.

Change-Id: I5b61e4f48c2d00d9d0a5305c9790093c66b3c765
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1600360
Commit-Queue: Johannes Henkel <johannes@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61355}