Rolling v8/build to 407cc11c28aef092dc961ff15e5530f50d235000

Rolling v8/tools/swarming_client to 380e32662312eb107f06fcba6409b0409f8fef72

TBR=machenbach@chromium.org,vogelheim@chromium.org,hablich@chromium.org

Review-Url: https://codereview.chromium.org/2304793002
Cr-Commit-Position: refs/heads/master@{#39113}