It's still unused there but now at least it ends up in the
feedback vector.

Bug: v8:6791
Change-Id: I0114d317830b80be4715c74dc5a8950fff4d3485
Reviewed-on: https://chromium-review.googlesource.com/829136Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50194}