Update to Xcode 16.1 #3141

Job	Run time
Check formatting	6s
Check MSRV	45s
Lint macOS x86_64	2m 27s
Lint iOS ARMv7s	2m 20s
Lint visionOS Aarch64 simulator	2m 17s
Lint GNUStep + exceptions	1m 18s
Lint header-translator	25s
Lint test-assembly	25s
Test macOS 15 Aarch64	1m 26s
Assembly tests	54s
Verify header translator output	50s
Check framework features	0s
${{ ((matrix.test && 'Test') \|\| 'Build') }} ${{ matrix.name }}	0s
Test GNUStep with libobjc2 v1.9	1m 2s
Test GNUStep with libobjc2 v2.0	1m 8s
Compiler UI	41s
Test Compiler-RT	20s
Test GNUStep with libobjc2 v2.1 on nightly	55s
Test on iOS simulator w. dinghy	0s
Test GNUStep 32bit	1m 3s
	18m 22s

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