Rolling v8/build to 0942801bf0d49016e44591d3e47ad3f41ad2d8a4

Rolling v8/buildtools to 031420bbafaaa8c33e2bc0623c22fb6181a57f47

Rolling v8/tools/mb to 18b92420fb0cb4378c9496b966507842b99d56b5

Rolling v8/tools/swarming_client to 7f63a272f7d9785ce41b6d10bb3106c49a968e57

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

Review-Url: https://codereview.chromium.org/2145303002
Cr-Commit-Position: refs/heads/master@{#37739}