scripts: add run_in_parallel helper for prod ops #55802

Job	Run time
optimize_ci	3s
check-system-test-trigger	51s
build_docker_images (sequencer, Dockerfile)	7m 36s
build_docker_images (dummy_exchange_rate_oracle, dummy_exchange_rate_oracle.Dockerfile)	3m 47s
build_docker_images (dummy_recorder, dummy_recorder.Dockerfile)	3m 50s
system_test_hybrid	2m 14s
	18m 21s

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