refactor: build starter kits before run

Build starter kits before run.
This will fail early if project can not be build at all.
This will also make run faster (app will be pre builds).

Author: dtopuzov

tests/templates/starter_kit_templates_tests.py

@@ -148,20 +148,27 @@ def tearDownClass(cls):
     @parameterized.expand(DEMOS)
     def test_000_prepare_apps(self, demo):
         Tns.create_app(demo, attributes={"--template": "https://github.com/NativeScript/" + demo})
+
         Tns.platform_add_android(attributes={"--path": demo, "--frameworkPath": ANDROID_PACKAGE})
+
         if "-ng" in demo:
             Tns.update_angular(demo)
         if "-ng" in demo or "-ts" in demo:
             Npm.uninstall(package="nativescript-dev-typescript", option='--save-dev', folder=demo)
             Npm.install(package=TYPESCRIPT_PACKAGE, option='--save-dev', folder=demo)
         Npm.uninstall(package="nativescript-dev-webpack", option='--save-dev', folder=demo)
+
         # Old webpack adds old webpack config. Cleanup to make sure we get the new config.
         File.remove(os.path.join(TEST_RUN_HOME, demo, 'webpack.config.js'))
         Tns.install_npm(package=WEBPACK_PACKAGE, option='--save-dev', folder=demo)
         Npm.uninstall(package="nativescript-dev-sass", option='--save-dev', folder=demo)
         Npm.install(package=SASS_PACKAGE, option='--save-dev', folder=demo)
+
+        Tns.build_android(attributes={'--path': demo})
+
         if CURRENT_OS == OSType.OSX:
             Tns.platform_add_ios(attributes={'--path': demo, '--frameworkPath': IOS_PACKAGE})
+            Tns.build_ios(attributes={'--path': demo})
 
     @parameterized.expand(DEMOS)
     def test_100_run_android(self, demo):