It'll replace the linux32 debug trybot in CQ soon when it's confirmed stable.

This also adds the corresponding MB config.

NOTRY=true
TBR=sergiyb@chromium.org

Change-Id: I99464d7d2d776390e59c48f0f65daa213a14f0f7
Reviewed-on: https://chromium-review.googlesource.com/1009746Reviewed-by: Sergiy Byelozyorov <sergiyb@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52564}