Rolling v8/buildtools to 0f8e6e4b126ee88137930a0ae4776c4741808740

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

Review URL: https://codereview.chromium.org/1569583003

Cr-Commit-Position: refs/heads/master@{#33145}