Intermitting `TestEthereumE2ESuite` failure - Log in goroutine after TestEthereumE2ESuite/TestFFIInvokeMethod has completed

[peterbroadhurst]

See https://github.com/hyperledger/firefly/runs/5052330826?check_suite_focus=true

2022-02-03T13:48:22.0579349Z     --- PASS: TestEthereumE2ESuite/TestFFIInvokeMethod (1.02s)
2022-02-03T13:48:22.0579603Z PASS
2022-02-03T13:48:22.0579931Z panic: Log in goroutine after TestEthereumE2ESuite/TestFFIInvokeMethod has completed
2022-02-03T13:48:22.0580150Z 
2022-02-03T13:48:22.0580249Z goroutine 189 [running]:
2022-02-03T13:48:22.0580528Z testing.(*common).logDepth(0xc0001e6f00, 0xc0003e1a80, 0x73, 0x3)
2022-02-03T13:48:22.0580877Z 	/opt/hostedtoolcache/go/1.16.13/x64/src/testing/testing.go:764 +0x5df
2022-02-03T13:48:22.0581155Z testing.(*common).log(...)
2022-02-03T13:48:22.0581464Z 	/opt/hostedtoolcache/go/1.16.13/x64/src/testing/testing.go:746
2022-02-03T13:48:22.0581790Z testing.(*common).Logf(0xc0001e6f00, 0xa063e7, 0x1f, 0xc0003e2f90, 0x2, 0x2)
2022-02-03T13:48:22.0582148Z 	/opt/hostedtoolcache/go/1.16.13/x64/src/testing/testing.go:792 +0x7e
2022-02-03T13:48:22.0582531Z github.com/hyperledger/firefly/test/e2e.wsReader.func1(0xc0004746e0, 0xc0001e6f00, 0xc000476240, 0xc0004761e0)
2022-02-03T13:48:22.0582929Z 	/home/runner/work/firefly/firefly/test/e2e/e2e_test.go:269 +0x49a
2022-02-03T13:48:22.0583258Z created by github.com/hyperledger/firefly/test/e2e.wsReader
2022-02-03T13:48:22.0583599Z 	/home/runner/work/firefly/firefly/test/e2e/e2e_test.go:265 +0xa5
2022-02-03T13:48:22.0583923Z FAIL	github.com/hyperledger/firefly/test/e2e	36.216s
2022-02-03T13:48:22.0584139Z FAIL