OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=31765
Crash type: Use-after-poison READ 8
Crash state:
std::__1::unique_ptr<SkSL::Expression, std::__1::default_delete<SkSL::Expression
SkSL::DefinitionMap::getKnownDefinition
SkSL::VariableReference::constantPropagate