Add unstable-no-link feature #2321

Job	Run time
Lint macOS 64bit	5m 2s
Check MSRV	1m 30s
Check formatting	12s
Lint iOS 32bit	1m 8s
Lint GNUStep + exceptions	2m 15s
Lint header-translator	40s
Lint test-assembly	30s
Test macOS 12	6m 10s
Verify header translator output	57s
Compiler UI	2m 1s
Assembly tests	1m 4s
Check icrate features	0s
Test Compiler-RT	44s
${{ matrix.name }}	0s
Test GNUStep with libobjc2 v1.9	2m 21s
Test on iOS simulator w. dinghy	0s
Test GNUStep with libobjc2 v2.0	2m 21s
Test GNUStep with libobjc2 v2.1 on nightly	3m 4s
Test GNUStep 32bit	2m 45s
	32m 44s

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