Restores some sensemaking properties, such as making src/machine-type.h (lower
level header) independent of src/zone/zone.h (higher level header).

BUG=v8:7490

Change-Id: Ibc6e5c7a75e4aaf917d086cf70267abc7ee9a9b0
Reviewed-on: https://chromium-review.googlesource.com/1039586Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52941}