mb_config.pyl: add new kitchen testing builders
mb_config.pyl: add new kitchen testing builders

BUG=chromium:593999
R=sergiyb@chromium.org, tandrii@chromium.org

Review URL: https://codereview.chromium.org/1886303002 .

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#387306}

axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk,axinging/chromium-crosswalk