multiregionccl: reenable TestMrSystemDatabase

I stressed this for a long time on many cores and it did not fail.

Epic: none

Fixes: #98039

Release note: None

pkg/ccl/multiregionccl/multiregion_system_table_test.go

@@ -26,7 +26,6 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlliveness/slstorage"
 	"github.com/cockroachdb/cockroach/pkg/testutils"
 	"github.com/cockroachdb/cockroach/pkg/testutils/serverutils"
-	"github.com/cockroachdb/cockroach/pkg/testutils/skip"
 	"github.com/cockroachdb/cockroach/pkg/testutils/sqlutils"
 	"github.com/cockroachdb/cockroach/pkg/util/leaktest"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
@@ -39,8 +38,6 @@ func TestMrSystemDatabase(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)
 
-	skip.WithIssue(t, 98039, "flaky test")
-
 	ctx := context.Background()
 
 	// Enable settings required for configuring a tenant's system database as multi-region.