schemachange: remove create schema workload from 20.2

The create schema method in workload/schemachange was not
backported to release 20.2. This change removes it to get
workload compiling.

Release note: None

pkg/workload/schemachange/schemachange.go

@@ -410,9 +410,6 @@ func (w *schemaChangeWorker) randOp(tx *pgx.Tx) (string, string, error) {
 		case createEnum:
 			stmt, err = w.createEnum(tx)
 
-		case createSchema:
-			stmt, err = w.createSchema(tx)
-
 		case dropColumn:
 			stmt, err = w.dropColumn(tx)
 
@@ -1177,17 +1174,6 @@ func (w *schemaChangeWorker) randType(tx *pgx.Tx) (tree.ResolvableTypeReference,
 	return rowenc.RandSortingType(w.rng), nil
 }
 
-func (w *schemaChangeWorker) createSchema(tx *pgx.Tx) (string, error) {
-	schemaName, err := w.randSchema(tx, 10)
-	if err != nil {
-		return "", err
-	}
-
-	// TODO(jayshrivastava): Support authorization
-	stmt := rowenc.MakeSchemaName(w.rng.Intn(2) == 0, schemaName, "")
-	return tree.Serialize(stmt), nil
-}
-
 func (w *schemaChangeWorker) randSchema(tx *pgx.Tx, pctExisting int) (string, error) {
 	if w.rng.Intn(100) >= pctExisting {
 		return fmt.Sprintf("schema%d", atomic.AddInt64(w.seqNum, 1)), nil