fix(@angular-devkit/build-angular): adjust chunk splitting options

This ensures that initial vendor modules are alway placed in the vendor bundle.  And also increases the potential for splitting common modules out of async (lazy route) chunks.

Mitigates angular/angular-cli#10294

Author: clydin

packages/angular_devkit/build_angular/src/angular-cli-files/models/webpack-configs/browser.ts

@@ -95,11 +95,13 @@ export function getBrowserConfig(wco: WebpackConfigOptions) {
       runtimeChunk: 'single',
       splitChunks: {
         chunks: buildOptions.commonChunk ? 'all' : 'initial',
+        maxAsyncRequests: Infinity,
         cacheGroups: {
           vendors: false,
           vendor: buildOptions.vendorChunk && {
             name: 'vendor',
             chunks: 'initial',
+            enforce: true,
             test: (module: any, chunks: Array<{ name: string }>) => {
               const moduleName = module.nameForCondition ? module.nameForCondition() : '';
               return /[\\/]node_modules[\\/]/.test(moduleName)