[apple-mobile][infra] Validate possibility of updating runtime queues from XCode 14 to 15 and iOS/tvOS 16 to 17

[matouskozak]

Why

We would like to merge osx.1200.amd64.iphone.open and osx.13.amd64.iphone.open queues together. However, the queues are using different macOS (12.4/13.3), XCode (13.4/14.3) and iOS (15.5/16.4) versions. To be able to merge them we need both queues to be at the same OS/XCode versions. The problem is that currently (08/19/2024) it is only possible to update to iOS 17 due to Apple update policies. Thus we need to verify that updating the queues to XCode 15 and iOS 17 won't cause unexpected failures on the CI.

While updating the iPhone queues to iOS 17, we should ideally also update the tvOS queue (osx.13.amd64.appletv.open) to the same version as well.

How

There are prepared scouting queues (osx.amd64.appletv.scouting.open, osx.amd64.iphone.scouting.open) that are setup with XCode 15 and iOS/tvOS 17 versions that can be used to verify if the update to higher version is possible. This can be done by manually opening (not merging) a PR which forces the CI jobs to use these scouting queues and observing the results. An example of previously opened PR: #88479.

What:

There are several repos/branches that use iOS/tvOS queues and need to be verified:

• dotnet/runtime main (.NET 10 currently)
• dotnet/runtime .NET 9 servicing (recent RC1 snap)
• dotnet/runtime .NET 8 servicing [release/8.0][no-merge][testing][infra] Try Apple mobile platforms on iOS 18 and XCode 16 #107021
• dotnet/runtime .NET 6 servicing (lower priority because .NET 6 is no longer supported on mobile apps)
• dotnet/xharness (uses osx.13.amd64.appletv.open and osx.13.amd64.iphone.open)
• dotnet/arcade (uses osx.13.amd64.appletv.open)
• Maybe more?

[dotnet-policy-service]

Tagging subscribers to 'os-tvos': @vitek-karas, @kotlarmilos, @ivanpovazan, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service]

Tagging subscribers to 'os-ios': @vitek-karas, @kotlarmilos, @ivanpovazan, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service]

Tagging subscribers to this area: @directhex, @matouskozak
See info in area-owners.md if you want to be subscribed.

[matouskozak]

This issue should be addressed after the scouting queues get updated to XCode 15.4 and macOS 14 dotnet/dnceng#3838.