refactor(@angular-devkit/build-angular): configure AOT compiler to skip class metadata in esbuild

The esbuild plugin used within the esbuild-based browser application builder will not use the
newly introduced internal `supportTestBed` AOT compiler option to disable the emit of class
metadata functions within the output code. This removes the need to perform an additional
transformation of the AOT compiler generated code to immediately remove the class metadata.
The class metadata is only needed when using TestBed with AOT generated code but testing
infrastructure within the CLI only performs unit-testing in JIT mode. In the future event,
that AOT enabled unit-testing is supported, this compiler option can be enabled for test
related builds.

Author: clydin

packages/angular_devkit/build_angular/src/builders/application/tests/behavior/angular-aot-metadata_spec.ts

@@ -0,0 +1,25 @@
+/**
+ * @license
+ * Copyright Google LLC 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 { buildApplication } from '../../index';
+import { APPLICATION_BUILDER_INFO, BASE_OPTIONS, describeBuilder } from '../setup';
+
+describeBuilder(buildApplication, APPLICATION_BUILDER_INFO, (harness) => {
+  describe('Behavior: "Angular metadata"', () => {
+    it('should not emit any AOT class metadata functions', async () => {
+      harness.useTarget('build', {
+        ...BASE_OPTIONS,
+      });
+
+      const { result } = await harness.executeOnce();
+      expect(result?.success).toBe(true);
+
+      harness.expectFile('dist/main.js').content.not.toContain('setClassMetadata');
+    });
+  });
+});

packages/angular_devkit/build_angular/src/tools/esbuild/angular/angular-compilation.ts

@@ -45,6 +45,7 @@ export abstract class AngularCompilation {
         allowEmptyCodegenFiles: false,
         annotationsAs: 'decorators',
         enableResourceInlining: false,
+        supportTestBed: false,
       }),
     );
   }