Rolling v8/tools/clang to 50155e1a5a647a6184e3fe2c687e2fbe1720d3e4

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

Review URL: https://codereview.chromium.org/1639253004

Cr-Commit-Position: refs/heads/master@{#33569}