[clang] [clang][ssaf] Add whole-program analysis execution layer (PR #186813)

[Nico Weber via cfe-commits]

nico wrote:

@aviralg, you seem to be landing commits differently from most others. If you `git log`, most commits have their PR number at the end of the commit message's first line, but yours don't.

(Not a big deal, but might want to look into what you're doing differently :))

https://github.com/llvm/llvm-project/pull/186813