Rolling v8/buildtools to a2082cafead67b75c9c8edbdca47a2def6dbab21

Rolling v8/tools/clang to 9dc1904d214a77f081362c1b848b5f28d2192748

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

Review URL: https://codereview.chromium.org/1876583002

Cr-Commit-Position: refs/heads/master@{#35367}