Rolling v8/build to 3f47a5e106127ae4e2567d64c615dc706054c819

Rolling v8/tools/clang to bd7e80b254a93d0a5cd8ecb994e47b1c827e253c

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

Review-Url: https://codereview.chromium.org/2347783002
Cr-Commit-Position: refs/heads/master@{#39461}