We don't need to compile project-level assets for every RuntimeIdentifier in
multi-rid builds, we can instead compile them just once in the outer build.
There is also a correctness issue here: we can't compile assets more than once
and expect to get the exact same compiled result every time (in particular
actool seems to be adding random bytes in to the compiled output), and this
creates a problem when trying to merge the different runtime-specific compiled
output into a universal binary.
We accomplish this by:
* Processing these assets in the outer build, before we execute the
rid-specific inner builds.
* Store the paths to the assets we've processed in a file.
* In the inner builds, we read that file, and remove any matches from the
corresponding item group.
* Make sure to copy the compiled assets to the app bundle at the end of the
outer build.
These are the assets we currently handle this way:
* BundleResource
* ImageAsset
* InterfaceDefinition
* SceneKitAsset
* Collada
* TextureAtlas
* CoreMLModel
Also:
* Add a new test case (AppWithResource) that contains all these different
types of assets.
* Add support for the ScnTool task on Mac Catalyst (which the new test case
revealed was missing).
Fixes https://github.com/xamarin/xamarin-macios/issues/12410.
9286bfb793