[clang] [Clang][C2y] Add support for if declarations (N3356 paper) (PR #198244)

[Vassil Vassilev via cfe-commits]

vgvassilev wrote:

I am wondering if we can do something to incrementally move forward. That is, is there some conservative subset of this pull request that can land and have the more focused discussions under smaller, incremental additions? That would allow @bassiounix to declare some level of progress and success as part of his work. 

https://github.com/llvm/llvm-project/pull/198244