run some tests concurrently where possible; improve package-scripts.js

[boneskull]

nps-utils makes this pretty easy.

I've cut a lot of time off of running tests locally using concurrent execution. CI remains to be seen...

[boneskull]

concurrently doesn't seem to allow a limit on how many processes to execute at once, which is problematic, since some just hang.

[boneskull]

I'm not seeing any significant speedup on Travis-CI with what I'm doing now, so maybe someone else has a better idea. To be clear: speeding up CI is the goal.

However, I am seeing a decent speedup in a local environment, which isn't surprising, given the way we partition the tests on Travis-CI. It's also considerably more difficult to understand what's happening, and way worse on Travis-CI, since there are no colors to help. Here are a couple screenshots:

My branch is here which I'll leave up for awhile, so you can see what I was trying to do.

[plroebuck]

You try setting process.env.FORCE_COLOR = 'true' first?

[juergba]

GH actions is running our CI tests in parallel, or concurrently?
Closing due to inactivity.