Update the ComputeInstructionSet task for Xcode 27

This is probably best done right after Apple's customary September event.

* [ ] Update the ComputeInstructionSet task with:
* New devices
* New CPUs
* Update max OS versions for devices that don't support the latest OS version.
* Remove any devices whose max OS version is lower than the earliest OS version we support.
* [ ] Create a new issue (copying this issue) for next year (Xcode 28).

Note: have in mind that AIs might struggle with this task, because it's based on potentially very recent data.

Ref: https://github.com/dotnet/macios/issues/24410