[clang] [clang][ssaf] Add JSONFormat support for WPASuite (PR #187403)

[Balázs Benics via cfe-commits]

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

I'm still exploring the metaprogramming space for alternative implementations, but I'll admit that it shouldn't block this PR for that. I'll continue in my free-time because I love tinkering with C++ metaprograms.

I found 2 gcc-7 blocker issues as I built this on my homelab machine.
Once those and the inline comments are addressed, let's merge this.

https://github.com/llvm/llvm-project/pull/187403