Enable advanced Java interop tests.

Add response parameters to custom_metadata streaming request for Node and PHP
clients.

The Java server does not respond with separate initial and trailing
metadata when there is no response data - it is only emiting the
requested trailing metadata. Adding the response parameters to the test
(in accordance with the specification) avoids this, but I will open a
separate issue to investigate the Java behavior.

src/node/interop/interop_client.js

@@ -312,6 +312,9 @@ function customMetadata(client, done) {
     }
   };
   var streaming_arg = {
+    response_parameters: [
+     {size: 314159}
+    ],
     payload: {
       body: zeroBuffer(271828)
     }

src/php/tests/interop/interop_client.php

@@ -451,11 +451,22 @@ function customMetadata($stub)
 
     $streaming_request = new grpc\testing\StreamingOutputCallRequest();
     $streaming_request->setPayload($payload);
+    $response_parameters = new grpc\testing\ResponseParameters();
+    $response_parameters->setSize($response_len);
+    $streaming_request->getResponseParameters()[] = $response_parameters;
     $streaming_call->write($streaming_request);
     $streaming_call->writesDone();
+    $result = $streaming_call->read();
 
     hardAssertIfStatusOk($streaming_call->getStatus());
 
+    $streaming_initial_metadata = $streaming_call->getMetadata();
+    hardAssert(array_key_exists($ECHO_INITIAL_KEY, $streaming_initial_metadata),
+               'Initial metadata does not contain expected key');
+    hardAssert(
+        $streaming_initial_metadata[$ECHO_INITIAL_KEY][0] === $ECHO_INITIAL_VALUE,
+        'Incorrect initial metadata value');
+
     $streaming_trailing_metadata = $streaming_call->getTrailingMetadata();
     hardAssert(array_key_exists($ECHO_TRAILING_KEY,
                                 $streaming_trailing_metadata),

tools/run_tests/run_interop_tests.py

@@ -179,10 +179,10 @@ class JavaLanguage:
     return {}
 
   def unimplemented_test_cases(self):
-    return _SKIP_ADVANCED + _SKIP_COMPRESSION
+    return _SKIP_COMPRESSION
 
   def unimplemented_test_cases_server(self):
-    return _SKIP_ADVANCED + _SKIP_COMPRESSION
+    return _SKIP_COMPRESSION
 
   def __str__(self):
     return 'java'