[clang] [X86][RFC] Refactor the SSE intrinsics constexpr tests to simplify future expansion (PR #112578)

[Phoebe Wang via cfe-commits]

https://github.com/phoebewang approved this pull request.

I like the idea to put them together, but I'm not expert in C++. It'd be good if someone familiar with C++ takes another look.

https://github.com/llvm/llvm-project/pull/112578