vmm: imporve observability to vmm-task & vmm-sandboxer #1327

Job	Run time
tests (vmm/sandbox, --all-features)	3m 47s
tests (vmm/task, --all-features)	3m 11s
checks (vmm/sandbox, --all-features)	4m 47s
tests (shim, --all-features)	2m 36s
checks (vmm/task, --all-features)	4m 18s
tests (quark, --all-features)	2m 43s
checks (shim, --all-features)	4m 10s
tests (runc, --all-features)	3m 8s
checks (quark, --all-features)	4m 1s
tests (wasm, --features=wasmedge, 0.13.5)	3m 21s
checks (runc, --all-features)	4m 30s
tests (wasm, --features=wasmtime)	3m 51s
checks (wasm, --features=wasmedge, 0.13.5)	4m 36s
checks (wasm, --features="wasmedge, wasmedge_wasi_nn", 0.13.5)	4m 41s
checks (wasm, --features=wasmtime)	4m 46s
	58m 26s

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