In the context of launching Liftoff, this will help us estimate the code
size increase and find a good value for the maximum allowed code space.

R=titzer@chromium.org

Bug: v8:6600
Change-Id: Ie76172edbf136629636911fe97c7ecdc940be86d
Reviewed-on: https://chromium-review.googlesource.com/1061497
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53220}