It seems unfair to completely kill linux-386, while we still provide minimal
best-effort support for more exotic platforms like linux-ppc64 or linux-s390x.

R=iannucci@chromium.org, tandrii@chromium.org
BUG=854300

Change-Id: Ia31ebb42f7e596c495b09bb99ecb376801256d55
Reviewed-on: https://chromium-review.googlesource.com/1111026Reviewed-by: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>