iOS testbed incompatible with Xcode 27

[freakboy3742]

Bug report

Bug description:

If you try to build and run the iOS testbed with Xcode 27, you will hit errors:

• The minimum supported iOS deployment target on projects is now 15.0, increased from 13.0
• iOS applications are now required to implement a UIScene-based application lifecycle.

The iOS testbed app needs to be updated to support these changes.

Both changes should be compatible with older Xcode versions. Setting a minimum iOS deployment target in the testbed doesn't mean changing the IPHONEOS_DEPLOYMENT_TARGET for the Python XCframework itself; and the UIScene APIs were introduced in iOS 13.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Other

Linked PRs

• gh-158051: Update testbed to support Xcode 27 #158052
• [3.15] gh-158051: Update testbed to support Xcode 27 (GH-158052) #158060
• [3.14] gh-158051: Update testbed to support Xcode 27 (GH-158052) #158061
• [3.13] gh-158051: Update testbed to support Xcode 27 (GH-158052) #158062

[freakboy3742]

Resolved by #158052 (and backports)