Report correct consumer count in paged list response (#4339)

Previously the Total in paged responses would always equal the size of
the first response this would stall paged clients after the first page.

Now correctly sets the total so paging continues, improves the test to
verify these aspects of the report

server/jetstream_cluster.go

@@ -6524,7 +6524,7 @@ LOOP:
 		})
 	}
 
-	resp.Total = len(resp.Consumers)
+	resp.Total = ocnt
 	resp.Limit = JSApiListLimit
 	resp.Offset = offset
 	resp.Missing = missingNames

server/norace_test.go

@@ -5387,6 +5387,9 @@ func TestNoRaceJetStreamClusterConsumerListPaging(t *testing.T) {
 		if resp.Limit < len(resp.Consumers) {
 			t.Fatalf("Expected total limited to %d but got %d", resp.Limit, len(resp.Consumers))
 		}
+		if resp.Total != numConsumers {
+			t.Fatalf("Invalid total response: expected %d got %d", numConsumers, resp.Total)
+		}
 		return resp.Consumers
 	}
 
@@ -5416,6 +5419,9 @@ func TestNoRaceJetStreamClusterConsumerListPaging(t *testing.T) {
 		if resp.Limit < len(resp.Consumers) {
 			t.Fatalf("Expected total limited to %d but got %d", resp.Limit, len(resp.Consumers))
 		}
+		if resp.Total != numConsumers {
+			t.Fatalf("Invalid total response: expected %d got %d", numConsumers, resp.Total)
+		}
 		return resp.Consumers
 	}
 
@@ -5432,6 +5438,10 @@ func TestNoRaceJetStreamClusterConsumerListPaging(t *testing.T) {
 			results[name] = true
 		}
 	}
+
+	if len(results) != numConsumers {
+		t.Fatalf("Received %d / %d consumers", len(results), numConsumers)
+	}
 }
 
 func TestNoRaceJetStreamFileStoreLargeKVAccessTiming(t *testing.T) {