Tests: support 'substrate-node' too and allow multiple binary paths #3038

Job	Run time
Check documentation and run doc tests	1m 34s
Cargo fmt	22s
Test Light Client	6s
Cargo check	1m 37s
Test non-wasm	1s
Cargo check (WASM)	1m 34s
Cargo clippy	46s
Test wasm	1m 38s
	7m 38s

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