Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/dbe38ca..24cce87

Rolling v8/tools/clang: https://chromium.googlesource.com/chromium/src/tools/clang/+log/58fecbe..68adbeb

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

Review-Url: https://codereview.chromium.org/2653123004
Cr-Commit-Position: refs/heads/master@{#42653}