[clang] [clang][dataflow] Factor out built-in boolean model into an explicit module. (PR #82950)

[Yitzhak Mandelbaum via cfe-commits]

ymand wrote:

Martin, I've thoroughly updated the refactoring, exactly as you suggested -- all of the interesting differences are actually just in how we handle the logical operations, so most of the changes are now in DataflowEnvironment.cpp.  I've left the factoring in Transfer because we may want it for the future -- these two models both use formulae, but other implementations could differ. 

The test failures are down to 35 and all they are all WAI -- places where we have genuine differences between the models, primarily around encoding custom API properties with formulae.

https://github.com/llvm/llvm-project/pull/82950