OSV-2020-1555 Global-buffer-overflow in OT::VarData::get_scalars

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=24504 Crash type: Global-buffer-overflow WRITE 4 Crash state: OT::VarData::getscalars OT::VariationStore::getscalars CFF::cff2csinterpenvt::processblend...