fixes#13160
- remove unused types
- use System.Numerics when possible
- move own created types from OpenTK namespace to CoreGraphics
- create missing types in CoreGraphics namespace
Co-authored-by: Rolf Bjarne Kvinge <rolf@xamarin.com>
* 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.