Rolling v8/tools/clang to a8288b3f25cdc4e3c3f4dd7ea2f7765ae8847459

Rolling v8/tools/swarming_client to df6e95e7669883c8fe9ef956c69a544154701a49

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

Review URL: https://codereview.chromium.org/1753133002

Cr-Commit-Position: refs/heads/master@{#34418}