Fix http2_interop test for c++ and python

src/python/grpcio_tests/tests/http2/negative_http2_client.py

@@ -96,8 +96,6 @@ def _rst_during_data(stub):
 
 def _rst_after_data(stub):
     resp_future = stub.UnaryCall.future(_SIMPLE_REQUEST)
-    _validate_payload_type_and_length(
-        next(resp_future), messages_pb2.COMPRESSABLE, _RESPONSE_SIZE)
     _validate_status_code_and_details(resp_future, grpc.StatusCode.INTERNAL,
                                       "Received RST_STREAM with error code 0")
 

test/cpp/interop/http2_client.cc

@@ -108,7 +108,7 @@ bool Http2Client::DoRstAfterData() {
 
   SimpleResponse response;
   AssertStatusCode(SendUnaryCall(&response), grpc::StatusCode::INTERNAL);
-  GPR_ASSERT(response.has_payload());  // data should be received
+  // There is no guarantee that data would be received.
 
   gpr_log(GPR_DEBUG, "Done testing reset stream after data");
   return true;