[libcxx-commits] [libcxx] [libc++][NFC] Simplify `optional<T>` and `optional<T&>` a bit (PR #203665)

[A. Jiang via libcxx-commits]

https://github.com/frederick-vs-ja requested changes to this pull request.

Current changes seemingly make `optional<T&>` have a wrong indirect base class for certain builds:
- generic-no-experimental
- clang-cl-debug, false, clang-cl, clang-cl
- clang-cl-dll, false, clang-cl, clang-cl
- clang-cl-no-vcruntime, false, clang-cl, clang-cl

We need to investigate what's going wrong.

https://github.com/llvm/llvm-project/pull/203665