Revert of Pool implementation for zone segments (patchset #9 id:420001 of https://codereview.chromium.org/2335343007/ )

Reason for revert:
Blocks Roll https://codereview.chromium.org/2366733002/

Original issue's description:
> Pool implementation for zone segments
>
> BUG=v8:5409
>
> Committed: https://crrev.com/37c688a24578e787d3d8941093563ed049c3497e
> Cr-Commit-Position: refs/heads/master@{#39631}

TBR=jkummerow@chromium.org,jochen@chromium.org,verwaest@chromium.org,heimbuef@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5409

Review-Url: https://codereview.chromium.org/2365843002
Cr-Commit-Position: refs/heads/master@{#39652}