Completion queue binding for new requests API change

Move completion queue binding for new requests to the new request
request time, not server instantiation time.
diff --git a/test/core/end2end/fixtures/chttp2_socket_pair.c b/test/core/end2end/fixtures/chttp2_socket_pair.c
index d19ceb1..43ebf7e 100644
--- a/test/core/end2end/fixtures/chttp2_socket_pair.c
+++ b/test/core/end2end/fixtures/chttp2_socket_pair.c
@@ -117,8 +117,8 @@
                                           grpc_channel_args *server_args) {
   grpc_endpoint_pair *sfd = f->fixture_data;
   GPR_ASSERT(!f->server);
-  f->server =
-      grpc_server_create_from_filters(f->server_cq, NULL, 0, server_args);
+  f->server = grpc_server_create_from_filters(NULL, 0, server_args);
+  grpc_server_register_completion_queue(f->server, f->server_cq);
   grpc_server_start(f->server);
   grpc_create_chttp2_transport(server_setup_transport, f, server_args,
                                sfd->server, NULL, 0, grpc_mdctx_create(), 0);