OSV-2020-1459 Segv on unknown address in clang::Sema::LookupQualifiedName

OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=19181 Crash type: Segv on unknown address Crash state: clang::Sema::LookupQualifiedName clang::Sema::CppLookupName clang::Sema::LookupName...