Add a composer script to allow FunctionalJavascript test suite to be run

+++ b/composer.json
@@ -109,6 +109,7 @@
+        "drupal-test-thing": "chromedriver --port=4444",

"drupal-test-thing"? 😂

I don't think that's gonna fly.

How about:

"drupal-prepare-javascript-tests"

or something?

Addressed the change mentioned in #17

Cool, thanks. Works for me.

Not sure that this adds much on its own. It depends how you have Chromedriver installed, so won't work for everyone, and there is no reference to this new command in any documentation so how will people discover it? There are docs in core/tests/README.md and at https://www.drupal.org/docs/automated-testing/phpunit-in-drupal/running-... → already, I think we should improve those if they aren't good enough.

Moving to NW for the README updates. Not sure if a separate ticket could be opened for the d.o docs page. Think you have to request permission to edit it.