OSV-2020-862 Use-of-uninitialized-value in std::__1::vector<std::__1::vector<Sass::Extension, std::__1::allocator<Sass::Ext

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=21223 Crash type: Use-of-uninitialized-value Crash state: std::1::vectorstd::1::vectorSass::Extension, std::1::allocatorSass::Ext Sass::Extender::extendCompound Sass::Extender::extendComplex...