After https://crrev.com/c/1789294, the {AddAndPublishAnonymousCode} has
only a single caller, {AddCodeForTesting}. Thus inline the method there.

R=mstarzinger@chromium.org

Change-Id: I698b37baa55221b82ead0b0bb8205233693ffced
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1789703
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63614}