Moving prototype from Google to GitHub

I'd started some prototyping work on this change before the move to
GitHub; this change restores things.
diff --git a/test/core/end2end/tests/max_concurrent_streams.c b/test/core/end2end/tests/max_concurrent_streams.c
index a418d1b..e2f30d0 100644
--- a/test/core/end2end/tests/max_concurrent_streams.c
+++ b/test/core/end2end/tests/max_concurrent_streams.c
@@ -113,9 +113,7 @@
   GPR_ASSERT(c);
 
   GPR_ASSERT(GRPC_CALL_OK ==
-             grpc_call_start_invoke(c, f.client_cq, tag(1), tag(2), tag(3), 0));
-  cq_expect_invoke_accepted(v_client, tag(1), GRPC_OP_OK);
-  cq_verify(v_client);
+             grpc_call_invoke(c, f.client_cq, tag(2), tag(3), 0));
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_call_writes_done(c, tag(4)));
   cq_expect_finish_accepted(v_client, tag(4), GRPC_OP_OK);
@@ -191,14 +189,17 @@
 
   GPR_ASSERT(GRPC_CALL_OK == grpc_server_request_call(f.server, tag(100)));
 
-  GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_invoke(c1, f.client_cq, tag(300),
+  GPR_ASSERT(GRPC_CALL_OK == grpc_call_invoke(c1, f.client_cq,
                                                     tag(301), tag(302), 0));
-  GPR_ASSERT(GRPC_CALL_OK == grpc_call_start_invoke(c2, f.client_cq, tag(400),
+  GPR_ASSERT(GRPC_CALL_OK == grpc_call_invoke(c2, f.client_cq,
                                                     tag(401), tag(402), 0));
+  GPR_ASSERT(GRPC_CALL_OK == grpc_call_writes_done(c1, tag(303)));
+  GPR_ASSERT(GRPC_CALL_OK == grpc_call_writes_done(c2, tag(303)));
+
   ev = grpc_completion_queue_next(
       f.client_cq, gpr_time_add(gpr_now(), gpr_time_from_seconds(10)));
   GPR_ASSERT(ev);
-  GPR_ASSERT(ev->type == GRPC_INVOKE_ACCEPTED);
+  GPR_ASSERT(ev->type == GRPC_FINISH_ACCEPTED);
   GPR_ASSERT(ev->data.invoke_accepted == GRPC_OP_OK);
   /* The /alpha or /beta calls started above could be invoked (but NOT both);
    * check this here */
@@ -206,11 +207,6 @@
   live_call_obj = live_call == 300 ? c1 : c2;
   grpc_event_finish(ev);
 
-  GPR_ASSERT(GRPC_CALL_OK ==
-             grpc_call_writes_done(live_call_obj, tag(live_call + 3)));
-  cq_expect_finish_accepted(v_client, tag(live_call + 3), GRPC_OP_OK);
-  cq_verify(v_client);
-
   cq_expect_server_rpc_new(v_server, &s1, tag(100),
                            live_call == 300 ? "/alpha" : "/beta",
                            "test.google.com", deadline, NULL);
@@ -232,11 +228,6 @@
                                  GRPC_STATUS_UNIMPLEMENTED, "xyz", NULL);
   live_call = (live_call == 300) ? 400 : 300;
   live_call_obj = live_call == 300 ? c1 : c2;
-  cq_expect_invoke_accepted(v_client, tag(live_call), GRPC_OP_OK);
-  cq_verify(v_client);
-
-  GPR_ASSERT(GRPC_CALL_OK ==
-             grpc_call_writes_done(live_call_obj, tag(live_call + 3)));
   cq_expect_finish_accepted(v_client, tag(live_call + 3), GRPC_OP_OK);
   cq_verify(v_client);