[compiler] Refactor Program to use queue of functions to compile

Refactors Program.ts to first traverse the `Program` node and build up a queue of functions to visit, then iterate that queue and compile the functions. This doesn't change behavior, but allows the next diff to add additional items to the queue during compilation (for function outlining).

ghstack-source-id: 858527c30ccc26b3aa6fe75a4746fce0820b316f
Pull Request resolved: https://github.com/facebook/react/pull/30330