These were originally written as part of
https://chromium-review.googlesource.com/c/550396/. I've separated them
out into a separate CL with the intent of landing it first, so that it's
easier to see the difference these CLs will have on generated bytecode.

BUG=v8:5855
TBR=tebbi@chromium.org, rmcilroy@chromium.org

Change-Id: Ib84e65847d7396e31b0e38d28f59454cf7c58fc1
Reviewed-on: https://chromium-review.googlesource.com/558221Reviewed-by: Caitlin Potter <caitp@igalia.com>
Commit-Queue: Caitlin Potter <caitp@igalia.com>
Cr-Commit-Position: refs/heads/master@{#46370}