sql: fix TestAtMostOneRunningCreateStats txn retry hang

Previously, this test could hang if there txn retry,
since we would end up waiting on a channel. To address
this patch will disable the testing knob once the channel
has been hit.

Fixes: #109007

Release note: None

pkg/sql/stats/create_stats_job_test.go

@@ -159,6 +159,9 @@ func TestCreateStatisticsCanBeCancelled(t *testing.T) {
 		errCh <- err
 	}()
 	allowRequest <- struct{}{}
+	// If we end up ever retrying the txn, we should not block on
+	// the allow request channel again.
+	setTableID(descpb.InvalidID)
 	testutils.SucceedsSoon(t, func() error {
 		row := conn.QueryRow("SELECT query_id FROM [SHOW CLUSTER STATEMENTS] WHERE query LIKE 'CREATE STATISTICS%';")
 		var queryID string
@@ -214,7 +217,6 @@ func TestAtMostOneRunningCreateStats(t *testing.T) {
 	case err := <-errCh:
 		t.Fatal(err)
 	}
-
 	autoStatsRunShouldFail := func() {
 		_, err := conn.Exec(`CREATE STATISTICS __auto__ FROM d.t`)
 		expected := "another CREATE STATISTICS job is already running"