Flip default for RLS on XDS being enabled to true. (#10248)

Author: larry-safran

xds/src/main/java/io/grpc/xds/XdsResourceType.java

@@ -47,7 +47,7 @@ abstract class XdsResourceType<T extends ResourceUpdate> {
   @VisibleForTesting
   static final String HASH_POLICY_FILTER_STATE_KEY = "io.grpc.channel_id";
   @VisibleForTesting
-  static boolean enableRouteLookup = getFlag("GRPC_EXPERIMENTAL_XDS_RLS_LB", false);
+  static boolean enableRouteLookup = getFlag("GRPC_EXPERIMENTAL_XDS_RLS_LB", true);
   @VisibleForTesting
   static boolean enableLeastRequest =
       !Strings.isNullOrEmpty(System.getenv("GRPC_EXPERIMENTAL_ENABLE_LEAST_REQUEST"))

xds/src/test/java/io/grpc/xds/XdsClientImplDataTest.java

@@ -172,7 +172,6 @@ public class XdsClientImplDataTest {
   @Before
   public void setUp() {
     originalEnableRouteLookup = XdsResourceType.enableRouteLookup;
-    assertThat(originalEnableRouteLookup).isFalse();
     originalEnableLeastRequest = XdsResourceType.enableLeastRequest;
     assertThat(originalEnableLeastRequest).isFalse();
     originalEnableWrr = XdsResourceType.enableWrr;