Intermittent Batch UnitTest failure: close of closed channel

[peterbroadhurst]

https://github.com/hyperledger/firefly/runs/4972849059?check_suite_focus=true

2022-02-03T21:43:11.6908946Z time="2022-02-03T21:43:11Z" level=debug msg="New message sequence notification: 12345" role=batch-newmessages
2022-02-03T21:43:11.6909490Z time="2022-02-03T21:43:11Z" level=debug msg="New message sequence notification: 12345" role=batch-newmessages
2022-02-03T21:43:11.6910018Z time="2022-02-03T21:43:11Z" level=error msg="Batch persist attempt 1 failed: pop" role=batchmgr
2022-02-03T21:43:11.6910507Z time="2022-02-03T21:43:11Z" level=error msg="update offset attempt 1: pop" role=batchmgr
2022-02-03T21:43:11.6910991Z time="2022-02-03T21:43:11Z" level=debug msg="Exiting due to close" role=batch-newmessages
2022-02-03T21:43:11.6911471Z time="2022-02-03T21:43:11Z" level=error msg="Batch persist attempt 2 failed: pop" role=batchmgr
2022-02-03T21:43:11.6911949Z time="2022-02-03T21:43:11Z" level=error msg="update offset attempt 2: pop" role=batchmgr
2022-02-03T21:43:11.6912253Z panic: close of closed channel
2022-02-03T21:43:11.6912384Z 
2022-02-03T21:43:11.6912487Z goroutine 9 [running]:
2022-02-03T21:43:11.6912813Z github.com/hyperledger/firefly/internal/batch.(*batchManager).Close(0xc000310960)
2022-02-03T21:43:11.6913356Z 	/home/runner/work/firefly/firefly/internal/batch/batch_manager.go:200 +0x24b
2022-02-03T21:43:11.6913834Z github.com/hyperledger/firefly/internal/batch.TestMessageSequencerUpdateBatchFail.func2(0xc000057c80, 0x2, 0x2)
2022-02-03T21:43:11.6914339Z 	/home/runner/work/firefly/firefly/internal/batch/batch_manager_test.go:476 +0x203
2022-02-03T21:43:11.6914760Z github.com/stretchr/testify/mock.(*Mock).MethodCalled(0xc0004023c0, 0x902ab7, 0xa, 0xc000057c80, 0x2, 0x2, 0xc0000a7280, 0x4, 0x4)
2022-02-03T21:43:11.6915205Z 	/home/runner/go/pkg/mod/github.com/stretchr/[email protected]/mock/mock.go:452 +0xa1a
2022-02-03T21:43:11.6915620Z github.com/stretchr/testify/mock.(*Mock).Called(0xc0004023c0, 0xc000057c80, 0x2, 0x2, 0xc00003d000, 0x0, 0xc0000a9c30)
2022-02-03T21:43:11.6916026Z 	/home/runner/go/pkg/mod/github.com/stretchr/[email protected]/mock/mock.go:383 +0x1ab
2022-02-03T21:43:11.6916468Z github.com/hyperledger/firefly/mocks/databasemocks.(*Plugin).RunAsGroup(0xc0004023c0, 0x8abc78, 0xc000331040, 0xc0000a7240, 0x0, 0x0)
2022-02-03T21:43:11.6916911Z 	/home/runner/work/firefly/firefly/mocks/databasemocks/plugin.go:2232 +0xb0
2022-02-03T21:43:11.6917345Z github.com/hyperledger/firefly/internal/batch.(*batchProcessor).persistBatch.func1(0x1, 0x47be05, 0x1, 0x96)
2022-02-03T21:43:11.6917791Z 	/home/runner/work/firefly/firefly/internal/batch/batch_processor.go:286 +0xfe
2022-02-03T21:43:11.6918473Z github.com/hyperledger/firefly/internal/retry.(*Retry).Do(0xc0003ee330, 0x8abc78, 0xc000331040, 0x82998d, 0xd, 0xc00015dde8, 0xc0000a9e28, 0x63d945)
2022-02-03T21:43:11.6918916Z 	/home/runner/work/firefly/firefly/internal/retry/retry.go:55 +0xad
2022-02-03T21:43:11.6919384Z github.com/hyperledger/firefly/internal/batch.(*batchProcessor).persistBatch(0xc0004f6c60, 0xc00035a1c0, 0xc0000a20a0, 0x1, 0x1, 0x1, 0x4, 0x89e900, 0x10, 0x7a41a0, ...)
2022-02-03T21:43:11.6919848Z 	/home/runner/work/firefly/firefly/internal/batch/batch_processor.go:285 +0x111
2022-02-03T21:43:11.6920264Z github.com/hyperledger/firefly/internal/batch.(*batchProcessor).persistenceLoop(0xc0004f6c60)
2022-02-03T21:43:11.6920687Z 	/home/runner/work/firefly/firefly/internal/batch/batch_processor.go:368 +0x4bc
2022-02-03T21:43:11.6921080Z created by github.com/hyperledger/firefly/internal/batch.newBatchProcessor
2022-02-03T21:43:11.6921497Z 	/home/runner/work/firefly/firefly/internal/batch/batch_processor.go:92 +0x50e