Since enabling the sandbox is now required for example for mkgrokdump,
add it to the default gn args. Also treat non-sandbox builds as
"non-shipping" in mkgrokdump.cc

Bug: v8:13281
Change-Id: I08042aa53057e25c556e166c059373e2fdb9d2c1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3899317
Commit-Queue: Samuel Groß <saelo@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#83231}