This CL changes the syntax for external constants to better reflect
for what they are actually used.

Drive-by change: Ran the format tool on base.tq.

R=danno@chromium.org, tebbi@chromium.org

Bug: v8:7793
Change-Id: Ie49c28b9c95a05846a2d9801f01b11e5a58d72d9
Reviewed-on: https://chromium-review.googlesource.com/1111706Reviewed-by: Daniel Clifford <danno@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#53963}