stack: compress shared stacks for clearer output #4281

Job	Run time
prepare	3s
binaries (darwin/amd64)	59s
binaries (darwin/arm64)	1m 17s
binaries (linux/amd64)	2m 1s
binaries (linux/arm/v7)	2m 8s
binaries (linux/arm64)	1m 54s
binaries (linux/s390x)	2m 7s
binaries (linux/ppc64le)	2m 0s
binaries (linux/riscv64)	2m 2s
binaries (windows/amd64)	1m 38s
binaries (windows/arm64)	1m 46s
test / prepare	1m 45s
test / run (containerd, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	8m 12s
test / run (containerd-rootless, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integr...	8m 55s
test / run (containerd-1.6, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	7m 27s
test / run (containerd-snapshotter-stargz, ./client ./cmd/buildctl ./worker/containerd ./solver ./fronte...	8m 33s
test / run (oci, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	5m 10s
test / run (oci-rootless, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, integration)	5m 24s
test / run (oci-rootless-slirp4netns-detachnetns, ./client ./cmd/buildctl ./worker/containerd ./solver ....	5m 30s
test / run (oci-snapshotter-stargz, ./client ./cmd/buildctl ./worker/containerd ./solver ./frontend, int...	5m 5s
test / run (./..., 1, integration gateway)	4m 3s
test / run (./client, containerd, nydus, integration)	7m 6s
test / run (./client, oci, nydus, integration)	5m 19s
test / run (./..., nydus, 1, integration)	4m 30s
image	9m 16s
image (rootless)	9m 28s
release	14s
	1h 53m 52s

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