add cwl-runner header to all CWL test files, mark them executable #929

Job	Run time
CI linters via Tox (lint-readme)	33s
CI linters via Tox (pydocstyle)	15s
CI tests via Tox (3, 9, lint)	17s
cwl-utils release test	5m 28s
CI tests via Tox (3, 9, unit)	2m 4s
CI tests via Tox (3, 9, bandit)	30s
CI tests via Tox (3, 9, mypy)	52s
CI tests via Tox (3, 10, lint)	21s
CI tests via Tox (3, 10, unit)	2m 32s
CI tests via Tox (3, 10, bandit)	23s
CI tests via Tox (3, 10, mypy)	48s
CI tests via Tox (3, 11, lint)	19s
CI tests via Tox (3, 11, unit)	2m 13s
CI tests via Tox (3, 11, bandit)	20s
CI tests via Tox (3, 11, mypy)	52s
CI tests via Tox (3, 12, lint)	15s
CI tests via Tox (3, 12, unit)	2m 14s
CI tests via Tox (3, 12, bandit)	26s
CI tests via Tox (3, 12, mypy)	52s
CI tests via Tox (3, 13, lint)	20s
CI tests via Tox (3, 13, unit)	2m 34s
CI tests via Tox (3, 13, bandit)	30s
CI tests via Tox (3, 13, mypy)	55s
	25m 53s

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