Added it to the V8-general config. Please let me know if it produces false positives/negatives and I'll try to adjust the detection config as needed.

For my own notes, here is what I did:
 - Added `internal.client.v8/*/v8/web-tooling-benchmark/*` to `V8 Perf Sheriff` config on https://chromeperf.appspot.com/edit_sheriffs
 - Added `internal.client.v8/*/v8/web-tooling-benchmark/*` to `V8-general config` on https://chromeperf.appspot.com/edit_anomaly_configs