[clang] [clang][NFC] Refactor `clang/test/SemaCXX/type-traits.cpp` to use modern `static_assert` (PR #77584)

[Amirreza Ashouri via cfe-commits]

AMP999 wrote:

@cor3ntin All checks are green now. Could you help me land this patch for me?

https://github.com/llvm/llvm-project/pull/77584