[Macros] Improve visitation of auxiliary decls
Use the same pattern as 'getAllMembers()'. This supports nested macro
expansion:
```
std::function<void(Decl *)> visit;
visit = [&](Decl *d) {
doIt(d);
d->visitAuxiliaryDecls(visit);
};
for (auto *d : decls)
visit(d);
```
Don't visit auxiliary decls in `PrintAST::visit(Decl *)` this function
is only intended for single decl printing. The caller should visit them
separately. For that, add
`ModuleDecl::getTopLevelDeclsWithAuxiliaryDecls()`
(cherry picked from commit 6f5283ebfc5bfe6426641297566864f2943a1490)
(cherry picked from commit 03bf34977835c4f080495c5cf50b22a1362b8bea)
(cherry picked from commit 55144fb302c3f2caa583d35904fb431ec04fbe2d)
