module: do not set CJS variables for Worker eval

src/node_contextify.cc

@@ -1708,6 +1708,8 @@ static void ContainsModuleSyntax(const FunctionCallbackInfo<Value>& args) {
     resource_name = args[2].As<String>();
   }
   // Argument 4: flag to indicate if CJS variables should not be in scope
+  // (they should be for normal CommonJS modules, but not for the
+  // CommonJS eval scope).
   bool cjs_var = !args[3]->IsString();
 
   bool cache_rejected = false;

test/es-module/test-esm-detect-ambiguous.mjs

@@ -408,7 +408,7 @@
 });
 
 describe('when working with Worker threads', () => {
-  it('should work', async () => {
+  it('should evaluate a CommonJS worker as valid sloppy script where the CommonJS wrapper variables do not exist', async () => {
     const { code, signal, stdout, stderr } = await spawnPromisified(process.execPath, [
       '--experimental-detect-module',
       '--eval',