JAVA-2393: Enable max staleness validity checks when read preference mode is primary preferred and the primary is available

Author: jyemin

driver-core/src/main/com/mongodb/TaggableReadPreference.java

@@ -379,7 +379,7 @@ public String getName() {
         @Override
         @SuppressWarnings("deprecation")
         protected List<ServerDescription> chooseForReplicaSet(final ClusterDescription clusterDescription) {
-            List<ServerDescription> selectedServers = clusterDescription.getPrimaries();
+            List<ServerDescription> selectedServers = selectFreshServers(clusterDescription, clusterDescription.getPrimaries());
             if (selectedServers.isEmpty()) {
                 selectedServers = super.chooseForReplicaSet(clusterDescription);
             }

driver-core/src/test/unit/com/mongodb/connection/ServerSelectionSelectionTest.java

@@ -71,9 +71,8 @@ public ServerSelectionSelectionTest(final String description, final BsonDocument
 
     @Test
     public void shouldPassAllOutcomes() {
-        // skip these tests because the driver prohibits maxStaleness or tagSets with mode of primary at a much lower level
+        // skip this test because the driver prohibits maxStaleness or tagSets with mode of primary at a much lower level
         assumeTrue(!description.equals("max-staleness/server_selection/ReplicaSetWithPrimary/MaxStalenessWithModePrimary.json"));
-        assumeTrue(!description.equals("max-staleness/server_selection/ReplicaSetWithPrimary/PrimaryPreferred_incompatible.json"));
 
         ServerSelector serverSelector = null;
         List<ServerDescription> suitableServers = buildServerDescriptions(definition.getArray("suitable_servers" , new BsonArray()));