Add wrapper around `dispatch_once_f` #3247

Job	Run time
Check formatting	10s
Check MSRV	58s
Lint macOS x86_64	1m 38s
Lint iOS ARMv7s	1m 44s
Lint visionOS Aarch64 simulator	1m 38s
Lint GNUStep + exceptions	59s
Lint header-translator	32s
Lint test-assembly	34s
Test macOS 15 Aarch64	2m 0s
${{ ((matrix.test && 'Test') \|\| 'Build') }} ${{ matrix.name }}	0s
Assembly tests	0s
Verify header translator output	0s
Check framework features	0s
Test Compiler-RT	0s
${{ matrix.name }}	0s
Compiler UI	0s
Test on iOS simulator w. dinghy	0s
	10m 13s

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