[clang] Fix const eval of constexpr-unknown relational comparisons.#150088

efriedma-quic merged 3 commits intollvm:mainllvm/llvm-project:mainfrom

efriedma-quic:constexpr-unknown-relational-arrayefriedma-quic/llvm-project:constexpr-unknown-relational-arrayCopy head branch name to clipboard