According to [this](https://github.com/w3c/webappsec-permissions-policy/blob/main/permissions-policy-explainer.md#appendix-big-changes-since-this-was-called-feature-policy), it should not accept `;`, only `,` as a separator character. It should produce a "We didn't detect a viable policy." error. Incorrect: <img width="1221" alt="pp_notok" src="https://user-images.githubusercontent.com/7722456/117363165-7f6f0900-aebc-11eb-898f-cc7ec82520cc.png"> Correct: <img width="1223" alt="pp_ok" src="https://user-images.githubusercontent.com/7722456/117363218-91e94280-aebc-11eb-929a-cdf49772da5b.png">
