Refactor integration test harness #1019

Job	Run time
unit-tests	45s
integration-tests (bitcoin-cln)	6m 59s
integration-tests (liquid-lnd)	5m 24s
integration-tests (liquid-cln)	6m 51s
integration-tests (lwk-lnd)	2m 43s
integration-tests (misc-integration)	5m 2s
integration-tests (bitcoin-lnd)	7m 2s
integration-tests (lwk-cln)	2m 41s
integration-tests (liquid-lnd)	5m 24s
integration-tests (liquid-cln)	6m 12s
integration-tests (lwk-lnd)	2m 43s
integration-tests (bitcoin-lnd)	7m 2s
integration-tests (bitcoin-cln)	6m 59s
unit-tests	45s
integration-tests (lwk-cln)	2m 41s
integration-tests (misc-integration)	5m 2s
unit-tests	45s
integration-tests (bitcoin-lnd)	6m 53s
integration-tests (bitcoin-cln)	7m 10s
integration-tests (liquid-cln)	6m 12s
integration-tests (lwk-cln)	2m 41s
integration-tests (liquid-lnd)	5m 24s
integration-tests (misc-integration)	5m 2s
integration-tests (lwk-lnd)	2m 43s
	1h 51m 5s

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