This removes dead classes and functions from utils.h.

R=sigurds@chromium.org

Bug: v8:9810, v8:8912
Change-Id: I8e15600f77b8ccc8ce25b4fd25e6a1b4303ad657
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1903969
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64853}