This is an unexciting CL (doesn't make the build step situation any better)
but enables moving FixedArray & co next.

BUG=v8:5402,v8:6474

Change-Id: Ia36eb3973e6242f6f68e02b9f583dc552d48422f
Reviewed-on: https://chromium-review.googlesource.com/529168
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45889}