test(progress-bar): add basic e2e tests

[crisbeto]

Adds basic e2e tests that assert that the different progress bars are being rendered.

Referencing #559.

[crisbeto]

@kara can you take a look at the menu e2e change? I wasn't sure what the reasoning behind the bottom: 200px was, but it ended up causing the menu test triggers to overlap, which in turn caused tests to fail. This was because the list of links above was getting too tall.

[kara]

@crisbeto Ack, I can't remember. I assume it had to do with triggers being clickable at some point, but if the e2e tests pass now, it probably is no longer necessary. LGTM.

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}