module: add builtinModules

Provides list of all builtin modules in Node.

Includes modules of all types:
- prefixed (ex: _tls_common)
- deprecated (ex: sys)
- regular (ex: vm)

lib/module.js

@@ -74,6 +74,12 @@ function Module(id, parent) {
 }
 module.exports = Module;
 
+const builtinModules = Object.keys(NativeModule._source)
+  .filter(NativeModule.nonInternalExists);
+
+Object.freeze(builtinModules);
+Module.builtinModules = builtinModules;
+
 Module._cache = Object.create(null);
 Module._pathCache = Object.create(null);
 Module._extensions = Object.create(null);