vmm: imporve observability to vmm-task & vmm-sandboxer #1233

Job	Run time
tests (vmm/sandbox, --all-features)	3m 36s
checks (vmm/sandbox, --all-features)	1m 39s
tests (vmm/task, --all-features)	2m 57s
checks (vmm/task, --all-features)	1m 23s
tests (shim, --all-features)	2m 35s
checks (shim, --all-features)	1m 40s
tests (quark, --all-features)	2m 28s
checks (quark, --all-features)	1m 41s
tests (runc, --all-features)	2m 49s
checks (runc, --all-features)	1m 40s
tests (wasm, --features=wasmedge, 0.13.5)	3m 37s
checks (wasm, --features=wasmedge, 0.13.5)	1m 41s
tests (wasm, --features=wasmtime)	3m 34s
checks (wasm, --features="wasmedge, wasmedge_wasi_nn", 0.13.5)	1m 41s
checks (wasm, --features=wasmtime)	1m 40s
	34m 41s

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