fix(@angular-devkit/build-angular): downlevel with non-loose ECMA com…

…pliance

This ensures that the ES5 bundles operate consistently with the ES2015+ bundles.

Fixes angular#15673

packages/angular_devkit/build_angular/src/utils/process-bundle.ts

@@ -65,10 +65,9 @@ async function processWorker(options: ProcessBundleOptions): Promise<void> {
     inputSourceMap: !manualSourceMaps && options.map !== undefined && JSON.parse(options.map),
     babelrc: false,
     // modules aren't needed since the bundles use webpacks custom module loading
-    // loose generates more ES5-like code but does not strictly adhere to the ES2015 spec (Typescript is loose)
     // 'transform-typeof-symbol' generates slower code
     presets: [
-      ['@babel/preset-env', { modules: false, loose: true, exclude: ['transform-typeof-symbol'] }],
+      ['@babel/preset-env', { modules: false, exclude: ['transform-typeof-symbol'] }],
     ],
     minified: true,
     sourceMaps: options.sourceMaps,