fix(compiler): remove i18n markup even if no translations (#17999)

Fixes #11042

packages/compiler-cli/integrationtest/test/basic_spec.ts

@@ -12,6 +12,7 @@ import * as path from 'path';
 import {MultipleComponentsMyComp} from '../src/a/multiple_components';
 import {BasicComp} from '../src/basic';
 import {createComponent} from './util';
+import {createComponentAlt} from './util_alt';
 
 describe('template codegen output', () => {
   const outDir = 'src';
@@ -88,5 +89,17 @@ describe('template codegen output', () => {
       const pText = pElement.children.map((c: any) => c.data).join('').trim();
       expect(pText).toBe('tervetuloa');
     });
+
+    it('should have removed i18n markup', () => {
+      const containerElement = createComponent(BasicComp).debugElement.children[0];
+      expect(containerElement.attributes['title']).toBe('käännä teksti');
+      expect(containerElement.attributes['i18n-title']).toBeUndefined();
+    });
+
+    it('should have removed i18n markup event without translations', () => {
+      const containerElement = createComponentAlt(BasicComp).debugElement.children[0];
+      expect(containerElement.attributes['title']).toBe('translate me');
+      expect(containerElement.attributes['i18n-title']).toBeUndefined();
+    });
   });
 });

packages/compiler-cli/integrationtest/test/util_alt.ts

@@ -0,0 +1,33 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {NgModuleRef} from '@angular/core';
+import {ComponentFixture} from '@angular/core/testing';
+import {platformServerTesting} from '@angular/platform-server/testing';
+
+import {MainModuleNgFactory} from '../alt/src/module.ngfactory';
+import {MainModule} from '../src/module';
+
+let mainModuleRef: NgModuleRef<MainModule> = null !;
+beforeEach((done) => {
+  platformServerTesting().bootstrapModuleFactory(MainModuleNgFactory).then((moduleRef: any) => {
+    mainModuleRef = moduleRef;
+    done();
+  });
+});
+
+export function createModule(): NgModuleRef<MainModule> {
+  return mainModuleRef;
+}
+
+export function createComponentAlt<C>(comp: {new (...args: any[]): C}): ComponentFixture<C> {
+  const moduleRef = createModule();
+  const compRef =
+      moduleRef.componentFactoryResolver.resolveComponentFactory(comp).create(moduleRef.injector);
+  return new ComponentFixture(compRef, null, false);
+}