ci: dump context on failure #1203

Job	Run time
prepare	1s
test / prepare	2m 32s
test / run (containerd, ./frontend/dockerfile, integration)	8m 27s
test / run (containerd, ./frontend/dockerfile, dockerfile)	12m 2s
test / run (containerd-rootless, ./frontend/dockerfile, integration)	8m 30s
test / run (containerd-rootless, ./frontend/dockerfile, dockerfile)	8m 55s
test / run (containerd-1.6, ./frontend/dockerfile, integration)	6m 39s
test / run (containerd-1.6, ./frontend/dockerfile, dockerfile)	9m 34s
test / run (containerd-snapshotter-stargz, ./frontend/dockerfile, integration)	7m 9s
test / run (containerd-snapshotter-stargz, ./frontend/dockerfile, dockerfile)	10m 49s
test / run (oci, ./frontend/dockerfile, integration)	6m 46s
test / run (oci, ./frontend/dockerfile, dockerfile)	8m 54s
test / run (oci-rootless, ./frontend/dockerfile, integration)	7m 57s
test / run (oci-rootless, ./frontend/dockerfile, dockerfile)	7m 45s
test / run (oci-snapshotter-stargz, ./frontend/dockerfile, integration)	7m 9s
test / run (oci-snapshotter-stargz, ./frontend/dockerfile, dockerfile)	8m 21s
image (mainline)	9m 22s
image (labs)	9m 4s
release	0s
	2h 19m 56s

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