OSV-2020-480 Use-of-uninitialized-value in _idn2_punycode_decode

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=13359 Crash type: Use-of-uninitialized-value Crash state: idn2punycodedecode tr46 idn2lookupu8...