Run Gauntlet validation, sanitizers, and Ubuntu 18 build/test as nightly actions.

[fruffy]

Save some CI resources on PRs.

[jafingerhut]

LGTM. I guess the resource you are most concerned with reducing here is the time spent waiting while the diffs in a PR are tested?

[fruffy]

@jnfoster The PR is blocked because validate is a required run. Can you disable it? In general, we should update the required CI runs.

[jafingerhut]

@jnfoster Do you know who the set of people is that has authorization to make the required steps for this to pass CI checks?

If it does not include @fruffy, I would be in favor of adding him to that set. Also anyone else you think would make sense to add to that set.

[jnfoster]

After discussing with the (informal) p4c maintainers, I've bumped up @fruffy's privileges on this repository. He should be able to modify CI configuration settings now.

[fruffy]

After discussing with the (informal) p4c maintainers, I've bumped up @fruffy's privileges on this repository. He should be able to modify CI configuration settings now.

Thank you!