In order to get more test coverage (also on ClusterFuzz), stage Liftoff
and tier up behind --future.

R=hablich@chromium.org
CC=​​titzer@chromium.org

Bug: v8:6600
Change-Id: I718e17957b26f60aa4c002333035f693344806e0
Reviewed-on: https://chromium-review.googlesource.com/1042385Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Hablich <hablich@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52987}