These allow to write a tagged uncompressed pointer even if pointer
compression is enabled. This is the least intrusive option; once
TurboFan supports pointer compression better, this CL likely
needs to be revised.

Bug: v8:8183
Change-Id: I56451c364b8620f687d8b9deb9553099ba95b928
Reviewed-on: https://chromium-review.googlesource.com/c/1445978
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59247}