tests: leverage job dependencies

[paulirish]

(This is a PR against #10988)

I mentioned this a while ago but you can use job.needs plus uploading/downloading artifacts to handle file dependencies between jobs: treosh/lighthouse-ci-action#40

so here's the setup:

• build job
  • test job
• smoke job

the diff is kinda useless but f1b68c4 has real meat of it.

---

on #10993:

1. the removal of yarn cache wfm. i wasn't ever too impressed with it. so i copied that here.
2. the smoke splitting is dope. didnt carry into this branch but we'll sort that out tomorrrow.

[connorjclark]

+1 to the semantical split of build + test. I had this during my iterations. I ended up removing it because there aren't a lot of actual dependencies in test on the dist/ artifact, so making the test job dependent on build 1) blurs what parts actually require build artifacts and 2) makes the test job take longer to start, finish, esp steps that 100% have no data dependency (lint, typecheck).

[paulirish]

yeah. all true.

and given that build-all is relatively fast.. i think it's the right call to make any child jobs depend on it.

okay great!