lib: expose primordials object

Expose the internal `primordials` object to help with Node.js core
development.

```console
$ node --expose-internals -r internal/test/binding lib/fs.js
(node:5299) internal/test/binding: These APIs are for internal testing
only. Do not use them.
(Use `node --trace-warnings ...` to show where the warning was created)
```

lib/internal/bootstrap/loaders.js

@@ -52,6 +52,7 @@ const {
   ObjectKeys,
   ObjectPrototypeHasOwnProperty,
   ReflectGet,
+  ReflectGetOwnPropertyDescriptor,
   SafeMap,
   SafeSet,
   String,
@@ -216,12 +217,19 @@ class NativeModule {
   }
 
   // Used by user-land module loaders to compile and load builtins.
-  compileForPublicLoader() {
+  compileForPublicLoader(isPreloading) {
     if (!this.canBeRequiredByUsers) {
       // No code because this is an assertion against bugs
       // eslint-disable-next-line no-restricted-syntax
       throw new Error(`Should not compile ${this.id} for public use`);
     }
+    if (isPreloading) {
+      ObjectDefineProperty(
+        this, 'isPreloading',
+        ReflectGetOwnPropertyDescriptor(
+          nativeModuleRequire('internal/modules/cjs/loader').Module.prototype,
+          'isPreloading'));
+    }
     this.compileForInternalLoader();
     if (!this.exportKeys) {
       // When using --expose-internals, we do not want to reflect the named

lib/internal/modules/cjs/helpers.js

@@ -32,11 +32,11 @@ let debug = require('internal/util/debuglog').debuglog('module', (fn) => {
 // TODO: Use this set when resolving pkg#exports conditions in loader.js.
 const cjsConditions = new SafeSet(['require', 'node', ...userConditions]);
 
-function loadNativeModule(filename, request) {
+function loadNativeModule(filename, request, isPreloading) {
   const mod = NativeModule.map.get(filename);
   if (mod) {
     debug('load native module %s', request);
-    mod.compileForPublicLoader();
+    mod.compileForPublicLoader(isPreloading);
     return mod;
   }
 }

lib/internal/modules/cjs/loader.js

@@ -781,7 +781,7 @@ Module._load = function(request, parent, isMain) {
     }
   }
 
-  const mod = loadNativeModule(filename, request);
+  const mod = loadNativeModule(filename, request, isPreloading);
   if (mod && mod.canBeRequiredByUsers) return mod.exports;
 
   // Don't call updateChildren(), Module constructor already does.

lib/internal/test/binding.js

@@ -4,4 +4,9 @@ process.emitWarning(
   'These APIs are for internal testing only. Do not use them.',
   'internal/test/binding');
 
-module.exports = { internalBinding };
+if (module.isPreloading) {
+  globalThis.internalBinding = internalBinding;
+  globalThis.primordials = primordials;
+}
+
+module.exports = { internalBinding, primordials };