feat(@schematics/angular): drop polyfills.ts file from new templates

With this change we drop the `polyfills.ts` from new application projects and add the polyfills directly in the `angular.json`. This is possible as now the `polyfills` option accept an array of module specifiers.

This change also fixes another open issue (#14432) which was caused by the missing polyfills file in the library test setup.

Closes #14432

Author: alan-agius4

packages/angular_devkit/build_angular/src/webpack/configs/common.ts

@@ -116,6 +116,10 @@ export async function getCommonConfig(wco: WebpackConfigOptions): Promise<Config
     // This is because the jasmine functions such as beforeEach/it will not be patched by zone.js since
     // jasmine will not be loaded yet, so the ProxyZone will not be there. We have to load zone-testing.js after
     // jasmine is ready.
+    // We could force loading 'zone.js/testing' prior to jasmine by changing the order of scripts in 'karma-context.html'.
+    // But this has it's own problems as zone.js needs to be loaded prior to jasmine due to patching of timing functions
+    // See: https://github.com/jasmine/jasmine/issues/1944
+    // Thus the correct order is zone.js -> jasmine -> zone.js/testing.
     const zoneTestingEntryPoint = 'zone.js/testing';
     const polyfillsExludingZoneTesting = polyfills.filter((p) => p !== zoneTestingEntryPoint);