Refactor integration test harness #1026

Job	Run time
unit-tests	47s
integration-tests (bitcoin_clncln)	5m 18s
integration-tests (bitcoin_mixed)	6m 37s
integration-tests (lnd)	3m 49s
integration-tests (bitcoin_lndlnd)	4m 21s
integration-tests (liquid_clncln)	5m 24s
integration-tests (liquid_lndlnd)	4m 19s
integration-tests (misc)	11m 15s
integration-tests (liquid_mixed)	6m 39s
unit-tests	47s
integration-tests (bitcoin_lndlnd)	4m 21s
integration-tests (bitcoin_mixed)	6m 37s
integration-tests (misc)	10m 48s
integration-tests (lnd)	3m 49s
integration-tests (bitcoin_clncln)	5m 18s
integration-tests (liquid_clncln)	5m 24s
integration-tests (liquid_mixed)	6m 39s
integration-tests (liquid_lndlnd)	4m 19s
integration-tests (misc)	10m 21s
integration-tests (liquid_lndlnd)	4m 19s
unit-tests	47s
integration-tests (bitcoin_clncln)	5m 18s
integration-tests (bitcoin_lndlnd)	4m 21s
integration-tests (bitcoin_mixed)	6m 37s
integration-tests (lnd)	3m 49s
integration-tests (liquid_clncln)	5m 24s
integration-tests (liquid_mixed)	6m 39s
	2h 24m 6s

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