Refactor message sending #2256

Job	Run time
Check formatting	16s
Lint macOS 64bit	4m 1s
Check MSRV	1m 43s
Lint iOS 32bit	1m 33s
Lint GNUStep + exceptions	1m 42s
Lint header-translator	38s
Lint test-assembly	31s
Test macOS 12	8m 34s
Verify header translator output	1m 25s
Compiler UI	2m 8s
Assembly tests	1m 11s
Check icrate features	0s
Test Compiler-RT	1m 18s
${{ matrix.name }}	0s
Test GNUStep with libobjc2 v1.9	2m 26s
Test on iOS simulator w. dinghy	0s
Test GNUStep with libobjc2 v2.0	2m 10s
Test GNUStep with libobjc2 v2.1 on nightly	2m 25s
Test GNUStep 32bit	2m 26s
	34m 27s

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