fix tests & address feedback

Change-Id: I44e660ab37999be0e98f71db3c089df03c123aad

Author: igorbernstein2

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/data/v2/BigtableDataClientFactoryTest.java

@@ -259,7 +259,8 @@ public void testCreateWithRefreshingChannel() throws Exception {
         BigtableDataSettings.newBuilderForEmulator(server.getPort())
             .setProjectId(DEFAULT_PROJECT_ID)
             .setInstanceId(DEFAULT_INSTANCE_ID)
-            .setAppProfileId(DEFAULT_APP_PROFILE_ID);
+            .setAppProfileId(DEFAULT_APP_PROFILE_ID)
+            .setRefreshingChannel(true);
     builder
         .stubSettings()
         .setCredentialsProvider(credentialsProvider)

google-cloud-bigtable/src/test/java/com/google/cloud/bigtable/data/v2/internal/csm/tracers/BuiltinMetricsTracerTest.java

@@ -508,9 +508,11 @@ public void onComplete() {
   public void testReadRowsApplicationLatencyWithManualFlowControl() throws Exception {
     int counter = 0;
 
-    for (Row ignored : stub.readRowsCallable().call(Query.create(TableId.of(TABLE)))) {
+    Iterator<Row> rows = stub.readRowsCallable().call(Query.create(TableId.of(TABLE))).iterator();
+    while (rows.hasNext()) {
       counter++;
       Thread.sleep(APPLICATION_LATENCY);
+      rows.next();
     }
 
     MetricData applicationLatency =