[clang] [Clang][Lex] Implement CWG3013: Error if #embed parameters were defined as macros (PR #224769)

[Ian Li via cfe-commits]

================

----------------
ianayl wrote:

My apologies about that, I hadn't seem that document. I've amended the tests and separated the C testing behavior into `embed_cxx_compat.c`, but admittedly it does feel a bit excessive to have basically copied `cwg3013.cpp` test file over; please let me know if you have any opinions on this. Thanks for the review btw!

https://github.com/llvm/llvm-project/pull/224769