Remove objc_alloc optimization from msg_send! #3375

Job	Run time
Check MSRV	58s
Lint macOS x86_64	3m 43s
Check formatting	14s
Lint iOS ARMv7s	4m 2s
Lint visionOS Aarch64 simulator	3m 58s
Lint GNUStep + exceptions	1m 28s
Lint header-translator	32s
Lint test-assembly	27s
Test macOS 15 Aarch64	2m 14s
Assembly tests	51s
Verify header translator output	2m 20s
${{ ((matrix.test && 'Test') \|\| 'Build') }} ${{ matrix.name }}	0s
Check framework features	0s
Test Compiler-RT	33s
Test GNUStep with libobjc2 v1.9	1m 14s
Compiler UI	46s
Test GNUStep with libobjc2 v2.0	1m 17s
Test on iOS simulator w. dinghy	0s
Test GNUStep with libobjc2 v2.1 on nightly	1m 6s
Test GNUStep 32bit	1m 37s
	27m 20s

Provide feedback