Add esm to core.

Author: jdalton

lib/internal/bootstrap/pre_execution.js

@@ -340,6 +340,8 @@ function initializeFrozenIntrinsics() {
 }
 
 function loadPreloadModules() {
+  require('internal/esm');
+
   // For user code, we preload modules if `-r` is passed
   const preloadModules = getOptionValue('--require');
   if (preloadModules) {

lib/internal/esm.js

@@ -120,6 +120,8 @@
       'lib/internal/encoding.js',
       'lib/internal/errors.js',
       'lib/internal/error-serdes.js',
+      'lib/internal/esm.js',
+      'lib/internal/esm/loader.js',
       'lib/internal/fixed_queue.js',
       'lib/internal/freelist.js',
       'lib/internal/freeze_intrinsics.js',