build(aio): add support for using the locally built Angular packages for aio

This commit allows building angular.io against the locally built Angular
packages. It adds two new npm scripts:

- `setup-local`: Same as `setup`, but overwrites the Angular packages for both
  angular.io and the examples boilerplate with the locally built ones.
- `build-local`: Same as `build`, but uses `setup-local` instead of `setup`
  under the hood, thus overwriting installed Angular packages with locally built
  ones.

Fixes #18611

scripts/ci/test-aio.sh

@@ -18,12 +18,6 @@ source ${thisDir}/_travis-fold.sh
   travisFoldEnd "test.aio.lint"
 
 
-  # Run unit tests for boilerplate tools
-  travisFoldStart "test.aio.boilerplate.unit"
-    yarn boilerplate:test
-  travisFoldEnd "test.aio.boilerplate.unit"
-
-
   # Run unit tests
   travisFoldStart "test.aio.unit"
     yarn test -- --single-run
@@ -38,7 +32,7 @@ source ${thisDir}/_travis-fold.sh
 
   # Run PWA-score tests
   travisFoldStart "test.aio.pwaScore"
-    yarn test-pwa-score-local
+    yarn test-pwa-score-localhost
   travisFoldEnd "test.aio.pwaScore"