lib: further simplify assertions in vm/module

Refs: #30755

PR-URL: #30815
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

lib/internal/vm/module.js

@@ -1,6 +1,6 @@
 'use strict';
 
-const { fail } = require('internal/assert');
+const assert = require('internal/assert');
 const {
   ArrayIsArray,
   ObjectCreate,
@@ -60,11 +60,6 @@ const kContext = Symbol('kContext');
 const kPerContextModuleId = Symbol('kPerContextModuleId');
 const kLink = Symbol('kLink');
 
-function failIfDebug() {
-  if (process.features.debug === false) return;
-  fail('VM Modules');
-}
-
 class Module {
   constructor(options) {
     emitExperimentalWarning('VM Modules');
@@ -120,12 +115,11 @@ class Module {
           importModuleDynamicallyWrap(options.importModuleDynamically) :
           undefined,
       });
-    } else if (syntheticEvaluationSteps) {
+    } else {
+      assert(syntheticEvaluationSteps);
       this[kWrap] = new ModuleWrap(identifier, context,
                                    syntheticExportNames,
                                    syntheticEvaluationSteps);
-    } else {
-      failIfDebug();
     }
 
     wrapToModuleMap.set(this[kWrap], this);
@@ -381,7 +375,9 @@ class SyntheticModule extends Module {
       identifier,
     });
 
-    this[kLink] = () => this[kWrap].link(() => { failIfDebug(); });
+    this[kLink] = () => this[kWrap].link(() => {
+      assert.fail('link callback should not be called');
+    });
   }
 
   setExport(name, value) {