test(aio): fix running docs examples against local builds (#18520)

This commit also updates the version of `@angular/cli` used for docs examples.
The previous (transient) dependency `@ngtools/webpack` was not compatible with
`@angular/compiler-cli@>=5` and was breaking when running against the local
builds (currently at 5.0.0-beta.2). The version of `@ngtools/webpack` used by
the latest `@angular/cli` version is compatible with `@angular/compiler-cli@5`.

aio/tools/examples/run-example-e2e.js

@@ -39,7 +39,7 @@ function runE2e() {
   if (argv.setup) {
     // Run setup.
     console.log('runE2e: copy boilerplate');
-    const spawnInfo = spawnExt('yarn', ['boilerplate:add', argv.local ? '-- --local': ''], { cwd: AIO_PATH });
+    const spawnInfo = spawnExt('yarn', ['boilerplate:add', '--', argv.local ? '--local' : ''], { cwd: AIO_PATH });
     promise = spawnInfo.promise
       .then(() => {
         console.log('runE2e: update webdriver');