* Fix many version checks to be based on Xcode version instead of iOS version.
* Added/fixed a few expected values according to platform version to match behavior in older macOS versions.
Fixesxamarin/xamarin-macios#3166
Apple broke `addAnimation:forKey:` API by changing `CAAnimation` parameter into a
`ISCNAnimationProtocol` that was introduced in Xcode 9 (iOS 11 and company).
We can't break the existing API but we can add an extension method that
reuses the `CAAnimation` overload but takes a `SCNAnimation` and we
turn the `SCNAnimation` into a `CAAnimation` behind the scenes.
For XAMCORE_4_0 we corrected the protocol signature to take `ISCNAnimationProtocol` so there won't be a need for the extension method anymore.
Largely related to somewhat recent frameworks/API additions to XM
ExternalAccessory was added to macOS 10.13 (Xcode9) and can't be run before that (including on the jenkins sierra bots). Also enable that test on tvOS (which added support in Xcode8)
Rolf Bjarne Kvinge
Alex Soto
Alex Soto
Sebastien Pouliot
Timothy Risi