Bundle spec files similar to how it is done within the Angular
Components repo. This should simplify the setup and also speed
up the Saucelab job as only a single spec bundle would need to be
downloaded, compared to having to load hundreds of files through the
Saucelabs tunnel.

Also makes a couple of tests more robust with the emulators/and accounts
for ES2015 test runner changes. The tests should be less reluctant to
such build process changes.

Note for reviewers: Some imports have been simplified here. This work
came from Joey's original WIP for this. It's unclear to me whether this
is still needed, but it sounded like this was necessary for the ESBuild
bundling to work. I have robusted the module resolution plugin though,
so I doubt it's still needed. At the same time though: Not worth
reverting/trying as these changes are nice to have anyway!

Co-Authored-By: Joey Perrott <josephperrott@gmail.com>
Co-Authored-By: Paul Gschwendtner <paulgschw...