[WIP] Support hybrid LTO/non-LTO rlibs. #4513

Job	Run time
rustfmt	13s
test_llvm	40s
dist (ubuntu-22.04, x86_64-unknown-linux-gnu)	1m 49s
bench	2m 2s
test (macos-15-intel, x86_64-apple-darwin)	4m 29s
test (windows-latest, x86_64-pc-windows-msvc)	4m 21s
todo_check	25s
dist (macos-latest, aarch64-apple-darwin)	2m 5s
test (windows-latest, x86_64-pc-windows-gnu)	4m 0s
dist (macos-15-intel, x86_64-apple-darwin)	3m 9s
test (macos-latest, aarch64-apple-darwin)	1m 46s
test (ubuntu-24.04-arm, aarch64-unknown-linux-gnu)	1m 49s
dist (ubuntu-24.04-arm, aarch64-unknown-linux-gnu)	1m 39s
dist (windows-latest, x86_64-pc-windows-msvc)	4m 28s
test (ubuntu-latest, x86_64-unknown-linux-gnu)	2m 8s
test (ubuntu-latest, riscv64gc-unknown-linux-gnu, gcc-riscv64-linux-gnu qemu-user)	2m 15s
test (ubuntu-latest, s390x-unknown-linux-gnu, gcc-s390x-linux-gnu qemu-user)	2m 24s
dist (windows-latest, x86_64-pc-windows-gnu)	4m 42s
release	0s
	44m 24s

Provide feedback