Refactor run_fixture tool, clean up ops #761

Job	Run time
tests (ubuntu-latest, tests)	47s
build (ubuntu-latest, noradio)	1m 52s
tests (macos-latest, tests)	41s
build (ubuntu-latest, wifi)	2m 11s
tests (windows-latest, tests_nosan)	1m 28s
build (ubuntu-latest, bt)	2m 2s
build (macos-latest, noradio)	1m 46s
build (macos-latest, wifi)	2m 1s
build (macos-latest, bt)	1m 34s
build (windows-latest, noradio)	6m 44s
build (windows-latest, wifi)	6m 14s
build (windows-latest, bt)	6m 8s
	33m 28s

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