Add test root readonly #2276

Job	Run time
youki-build (x86_64, gnu)	1m 41s
youki-build (x86_64, musl)	2m 10s
youki-build (aarch64, gnu)	1m 53s
youki-build (aarch64, musl)	2m 0s
oci-validation-rust (x86_64, gnu)	3m 5s
oci-validation-rust (x86_64, musl)	2m 40s
oci-validation-go (x86_64, gnu)	1m 55s
oci-validation-go (x86_64, musl)	2m 18s
containerd-integration-tests (x86_64, gnu)	4m 52s
k8s-tests (x86_64, gnu)	4m 27s
containerd-integration-tests (x86_64, musl)	4m 42s
k8s-tests (x86_64, musl)	1m 24s
rootless-podman-test (x86_64, gnu)	40s
rootless-podman-test (x86_64, musl)	54s
docker-in-docker (ubuntu-22.04)	19s
docker-in-docker (ubuntu-20.04)	11s
	35m 11s

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