module: introduce defaultModuleName in module.js

This commit adds a constant named defaultModuleName to avoid duplicating
it in the Module constructor function.

PR-URL: #20709
Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/internal/vm/module.js

@@ -48,6 +48,7 @@ const linkingStatusMap = new WeakMap();
 const initImportMetaMap = new WeakMap();
 // ModuleWrap -> vm.Module
 const wrapToModuleMap = new WeakMap();
+const defaultModuleName = 'vm:module';
 
 class Module {
   constructor(src, options = {}) {
@@ -82,13 +83,13 @@ class Module {
       }
       url = new URL(url).href;
     } else if (context === undefined) {
-      url = `vm:module(${globalModuleId++})`;
+      url = `${defaultModuleName}(${globalModuleId++})`;
     } else if (perContextModuleId.has(context)) {
       const curId = perContextModuleId.get(context);
-      url = `vm:module(${curId})`;
+      url = `${defaultModuleName}(${curId})`;
       perContextModuleId.set(context, curId + 1);
     } else {
-      url = 'vm:module(0)';
+      url = `${defaultModuleName}(0)`;
       perContextModuleId.set(context, 1);
     }