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This adds build configs for a devtools release trybot for running blink
layout tests.

TBR=jbudorick@chromium.org

Bug: 1016290
Change-Id: Ieb73cdd6786545a1216165b5cc701c8628182a56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1872092Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708109}