Add a HelixQueues attribute.

[mitchdenny]

This PR adds a [HelixQueues] attribute. The goal of this attribute is to allow us to succinctly opt-in to a specific queue once without having to exclude all other queues - that said, the usage is a bit more flexible than that and it could potentially replace the existing [SkipOnHelix] attribute. Usage:

[HelixQueues(Includes = HelixConstants.NativeAotSupportedQueues)]
public void MyTestMethod()
{
}

You can also specify excludes:

[HelixQueues(Includes = "*", Excludes = "All.Windows")]
public void MyTestMethod()
{
}

This PR also adds "All.Windows" as a special value along-side the existing "All.OSX" and "All.Ubuntu" values.

[ghost]

Hey @dotnet/aspnet-build, looks like this PR is something you want to take a look at.

[BrennanConroy]

An issue with this attribute is that if we change a queue any tests that "target" that queue will silently stop running.

[mitchdenny]

That is a fair point. The flip-side is that for some tests, like the AOT tests presently - every time we add a new queue the tests start breaking which is a pain.

[BrennanConroy]

IMO visibility (and a little pain of fixing broken tests) is far better than silently not running tests.

[mitchdenny]

Upon reflection, I think I agree with you. As painful as this is :) .... (having to remove queues occasionally, not agreeing with you)