Add variant exclusion per-project in DSL

[joshfriend]

We have a lot of fake/demo/testing style projects that are only intended for consumption by debug variant apps. Some of these have only debug/ sourcesets. In a perfect world, we would use single-variant android libraries and rely on other tooling to ensure these projects never end up in release builds. Our current state leaves us with a lot of complications if we try to run analysis on both debug and release variants because these debug-only projects often fail to compile in the release configuration, or we are just wasting time by analyzing releaseUnitTest stuff.

I'd propose this as an intermediate solution until a v3.0 where we might have a more advanced DSL for exclusions. What I'd really like to do is be able to exclude release variants for test source sets everywhere.

[autonomousapps]

Why is this on the AbiHandler? The way it's used, it looks like it's causing the variant to be ignored for all use-cases, not just ABI analysis. And given that, why isn't the existing functionality to ignore specific source sets sufficient?

[joshfriend]

Why is this on the AbiHandler?

I got it mixed up with the ProjectIssueHandler handler, what I was going for was a project specific version of the global property dependency.analysis.android.ignored.variants that exists currently.

why isn't the existing functionality to ignore specific source sets sufficient?

If I have an Android project with only a debug/ source set, and I use ignoreSourceSet('release') DAGP still compiles and analyzes the variant (or it tries to and fails because the release configuration of some of these debug-only projects is often broken).