streamingccl: reduce scan interval for testing

Reduce the replica scanner min interval from 1s, to 10ms for test
clusters. This speeds up tests which rely on replica changes either on
the source, or host cluster.

```
dev test pkg/ccl/streamingccl/streamingest \
  -f TestStreamingRegionalConstraint -v --stress
...
Stats over 1000 runs: max = 51.9s, min = 21.6s, avg = 38.3s, dev = 4.6s
```

Resolves: #112541
Release note: None

pkg/ccl/streamingccl/replicationtestutils/testutils.go

@@ -357,6 +357,7 @@ func startC2CTestCluster(
 		for i, locality := range regions {
 			param := serverArgs
 			param.Locality = makeLocality(locality)
+			param.ScanMaxIdleTime = 10 * time.Millisecond
 			serverArgsPerNode[i] = param
 		}
 		params.ServerArgsPerNode = serverArgsPerNode

pkg/ccl/streamingccl/streamingest/replication_stream_e2e_test.go

@@ -1170,7 +1170,6 @@ func TestStreamingRegionalConstraint(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)
 	skip.UnderStressRace(t, "takes too long under stress race")
-	skip.UnderStress(t, "the allocator machinery stuggles with cpu contention, which can cause the test to timeout")
 
 	ctx := context.Background()
 	regions := []string{"mars", "venus", "mercury"}
@@ -1204,7 +1203,8 @@ func TestStreamingRegionalConstraint(t *testing.T) {
 				for _, desc := range descriptors {
 					for _, replica := range desc.InternalReplicas {
 						if replica.NodeID != marsNodeID {
-							return errors.Newf("found table data located on another node %d", replica.NodeID)
+							return errors.Newf("found table data located on another node %d, desc %v",
+								replica.NodeID, desc)
 						}
 					}
 				}