OSV-2017-109 Use-of-uninitialized-value in Unpack::MakeDecodeTables

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4298 Crash type: Use-of-uninitialized-value Crash state: Unpack::MakeDecodeTables Unpack::ReadTables20 Unpack::Unpack20...