Refactor integration test harness #1027

Job	Run time
unit-tests	53s
integration-tests (bitcoin_lndlnd)	4m 14s
integration-tests (liquid_mixed)	7m 14s
integration-tests (liquid_lndlnd)	4m 17s
integration-tests (bitcoin_clncln)	5m 17s
integration-tests (misc)	7m 28s
integration-tests (liquid_clncln)	5m 15s
integration-tests (bitcoin_mixed)	6m 32s
integration-tests (lnd)	4m 1s
integration-tests (bitcoin_clncln)	5m 17s
integration-tests (misc)	10m 40s
integration-tests (liquid_clncln)	5m 15s
integration-tests (liquid_mixed)	7m 14s
integration-tests (liquid_lndlnd)	4m 17s
unit-tests	53s
integration-tests (bitcoin_lndlnd)	4m 14s
integration-tests (lnd)	4m 1s
integration-tests (bitcoin_mixed)	6m 32s
integration-tests (misc)	10m 40s
integration-tests (bitcoin_clncln)	5m 17s
integration-tests (liquid_mixed)	6m 34s
unit-tests	53s
integration-tests (bitcoin_mixed)	6m 32s
integration-tests (lnd)	4m 1s
integration-tests (liquid_clncln)	5m 15s
integration-tests (liquid_lndlnd)	4m 17s
integration-tests (bitcoin_lndlnd)	4m 14s
	2h 21m 17s

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