Output mode cannot work without a DB connection

[breezewish]

~ go-tpc tpch --sf=50 --output-dir=tpch50 --output-type=csv prepare
[mysql] 2022/04/01 01:29:25 packets.go:36: unexpected EOF
[mysql] 2022/04/01 01:29:37 packets.go:36: unexpected EOF
[mysql] 2022/04/01 01:29:50 packets.go:36: unexpected EOF
cannot connect to the database

[dbsid]

Yes，it's a known limitation. Will check if we can do it without a db connection.