[Benchmark] fail test if model artifact does not exist #592

Job	Run time
set-parameters	8s
build-benchmark-app / linux-job	20m 45s
export-models (llama, qnn_q8, samsung_galaxy_s22, arn:aws:devicefarm:us-west-2:308535385114:devic... / linux-job	37m 25s
export-models (llama, xnnpack_q8, samsung_galaxy_s22, arn:aws:devicefarm:us-west-2:308535385114:d... / linux-job	10m 58s
prepare-test-specs (llama, xnnpack_q8, samsung_galaxy_s22, arn:aws:devicefarm:us-west-2:308535385...	48s
prepare-test-specs (llama, qnn_q8, samsung_galaxy_s22, arn:aws:devicefarm:us-west-2:308535385114:...	41s
benchmark-on-device (llama, qnn_q8, samsung_galaxy_s22, arn:aws:devicefarm:us-west-2:308535385114... / mobile-job (android)	1m 5s
benchmark-on-device (llama, xnnpack_q8, samsung_galaxy_s22, arn:aws:devicefarm:us-west-2:30853538... / mobile-job (android)	59s
upload-benchmark-results	1m 2s
	1h 13m 51s

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