roachtest/import: refactor existing roachtests for import

Previously, the roachtests for import were distressingly absent solid
verification of the imported data. This patch changes those tests to use
the newly revamed SHOW FINGERPRINTS to validate the imported data. Along
the way, we attempt to standardize and rationalize the test design so
that it's more easily extensible.

As part of this work, we're moving away from using TPC-C data even though
it most closely resembles OLTP workloads because it's much easier to
validate the import of the static TPC-H data files. We keep the TPC-C
benchmark because that's potentially interesting, but it's a separate
thing for now.

We also now standardize how we deal with local clusters by picking a
scale factor during data set initialization. Local uses scale factor 1
and our four node tests use scale factor 100. The data set initializer
has access to the cluster configuration, so we can select even larger
scale factors for larger clusters in the future, if desired.

Informs: cockroachdb#156816
Release note: None

Author: mw5h

pkg/cmd/roachtest/tests/backup.go

@@ -626,7 +626,7 @@ func runBackupMVCCRangeTombstones(
 	require.NoError(t, err)
 	_, err = conn.Exec(`USE tpch`)
 	require.NoError(t, err)
-	createStmt, err := readCreateTableFromFixture(
+	createStmt, err := readFileFromFixture(
 		"gs://cockroach-fixtures-us-east1/tpch-csv/schema/orders.sql?AUTH=implicit", conn)
 	require.NoError(t, err)
 	_, err = conn.ExecContext(ctx, createStmt)