This reserves space in a newly several newly created vectors before
pushing a known number of elements.

Change-Id: If3ba016395e7b509ced549b57279a049125c5d7c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2649034Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72318}