workloadccl: mark tpccmultidb as bigInitialData

We already skip `tpcc` in `bigInitialData`, and I think it was a mistake
that `tpccmultidb` wasn't marked in the same way. In particular, this
will make it so that we don't run some of the test cases.

The reason I was looking into this is that
`TestAllRegisteredSetup/tpccmultidb` took 9 minutes on CI with external
process mode. I couldn't quickly speed that up (e.g. exempting from rate
limiting didn't help), but skipping it will work just fine.

Release note: None

Author: yuzefovich

pkg/ccl/workloadccl/allccl/all_test.go

@@ -34,7 +34,7 @@ import (
 
 func bigInitialData(meta workload.Meta) bool {
 	switch meta.Name {
-	case `tpcc`, `tpch`, `tpcds`:
+	case `tpcc`, `tpch`, `tpcds`, `tpccmultidb`:
 		return true
 	default:
 		return false