OSV-2021-1052 Use-of-uninitialized-value in jxl::N_AVX2::UpsampleRect

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=36497 Crash type: Use-of-uninitialized-value Crash state: jxl::NAVX2::UpsampleRect jxl::Upsampler::UpsampleRect jxl::FinalizeImageRect...