Update V8 DEPS.
Update V8 DEPS.

Rolling v8/tools/clang to 4943801a353f2f58e7268e17803d87cf78f2f732

TBR=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1253623002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29793}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh