This reverts commit 133a6815.

Reason for revert: Regresses parsing time

Original change's description:
> [cleanup] Replace ZoneList with ZoneVector for parser reported_errors_
> 
> We use a ZoneVector because we do a fair amount of random access e.g.
> in ExpressionClassifier::Accumulate() so the vector is better suited
> than ZoneChunkList as it has constant time random access.
> 
> Bug: v8:6333
> Change-Id: I83e1de60ee8fe319cfa5ce77fc5f5f86beb5307d
> Reviewed-on: https://chromium-review.googlesource.com/1054672
> Reviewed-by: Georg Neis <neis@chromium.org>
> Commit-Queue: Peter Marshall <petermarshall@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#55315}

TBR=neis@chromium.org,petermarshall@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: v8:6333
Change-Id: Ib89f0aa1f27b7d6dbbf21af60ed7d1bcd2c0b7d3
Reviewed-on: https://chromium-review.googlesource.com/1189803Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55427}