The missing include causes compilation failures for node.js, see
https://github.com/nodejs/node/pull/30020.

It's not great to have includes in a file called "macros.h", but we
define several functions there that make use of type traits. Fixing
that is a separate project.

R=mlippautz@chromium.org

Change-Id: Idb067679e597521230f94eb8c99f1347ed3808cb
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1868622Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64386}