OSV-2021-618 Heap-buffer-overflow in OT::AnchorFormat1* hb_serialize_context_t::embed<OT::AnchorFormat1>

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=33031 Crash type: Heap-buffer-overflow READ 6 Crash state: OT::AnchorFormat1 hbserializecontextt::embed OT::AnchorFormat1::copy OT::Anchor::subset...