This is another step in the direction of #13414. It makes it possible to use named imports for types, tokTypes, traverse and template from @babel/core, which were not available because the Node.js CJS-ESM interop doesn't recognize our lazy reexports.

Basically this code:

Object.defineProperty(exports, "types", {
  enumerable: true,
  get: function () {
    return _types();
  }
});

Is replaced by this (which is detected by the Node.js interpo) by a custom plugin:

Object.defineProperty((0, exports), "types", {
  enumerable: true,
  get: function () {
    return _types();
  }
});
0 && (exports.types = 0);

The second commit removes the usage of @babel/core's default export in our tests, which in theory shouldn't exist.