Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/83f770a..0676437

Rolling v8/tools/clang: https://chromium.googlesource.com/chromium/src/tools/clang/+log/d48a09f..7f925e3

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

Review-Url: https://codereview.chromium.org/2551003002
Cr-Commit-Position: refs/heads/master@{#41470}