Add NEXT_PRIVATE_SKIP_CANARY_CHECK env for bench job #20061

# to view logs

Job	Run time
deploy-target	13s
publish-turbopack-npm-packages	0s
build	2m 14s
stable - x86_64-unknown-linux-gnu - node@16	45s
build-wasm (web)	21s
build-wasm (nodejs)	19s
Upload Turbopack Bytesize metrics to Datadog	0s
Deploy preview tarball	1m 52s
Potentially publish release	0s
Deploy examples	0s
Release Stats	0s
	5m 44s

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