test(@angular-devkit/build-webpack): use Ivy Webpack plugin in unit tests

The ViewEngine-based Webpack compiler has now been removed.

Author: clydin

packages/angular_devkit/build_webpack/test/angular-app/webpack.config.js

@@ -19,8 +19,8 @@ module.exports = {
     filename: `[name].js`,
   },
   plugins: [
-    new ngToolsWebpack.AngularCompilerPlugin({
-      tsConfigPath: path.resolve(projectRoot, './src/tsconfig.app.json')
+    new ngToolsWebpack.AngularWebpackPlugin({
+      tsconfig: path.resolve(projectRoot, './src/tsconfig.app.json')
     })
   ],
   module: {