This allows to hold a constexpr (empty) "builder" object instead of
creating it for every use.

R=ahaas@chromium.org

Bug: v8:11384
Change-Id: Ib5e13c58e81a950bb5dd0e8eefe4021bc77d8b64
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2773801
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73548}