It's not necessarily helpful, and can actually cause pretty bad performance and
memory usage.

I moved up the next_ field to where allocation_ used to be since apparently the
alignment caused by it has huge impact on perf (>10% diff...) at least on my
machine.

Change-Id: I1026a2e954d061b1a178f6a733d8ef81ae6d0cab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1594432
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61250}