roachtest: copy/bank/rows=10000000,nodes=9,txn=true failed

SHA: https://github.com/cockroachdb/cockroach/commits/eed443af32474fd76d3b860b44ebfa339b249703

Parameters:

Failed test: https://teamcity.cockroachdb.com/viewLog.html?buildId=783566&tab=buildLog

```
	test.go:499,copy.go:120,cluster.go:1077,errgroup.go:58: failed to copy rows: pq: TransactionStatusError: transaction deadline exceeded (REASON_UNKNOWN)

```