build: remove manual tags from platform jasmine tests (#26606)

PR Close #26606

packages/platform-browser-dynamic/test/testing_public_browser_spec.ts

@@ -37,7 +37,7 @@ class BadTemplateUrl {
 
 // Tests for angular/testing bundle specific to the browser environment.
 // For general tests, see test/testing/testing_public_spec.ts.
-{
+if (isBrowser) {
   describe('test APIs for the browser', () => {
     describe('using the async helper', () => {
       let actuallyDone: boolean;