Partially revert delegate optimisation

That was done in PR #3865.

The changes introduced in #3865 can cause message arrival ordering guarantees
between two logical erlang process (sending messages via delegate) to
be violated as a message sent to a single destination can overtake a prior
message sent as part of a fan-out. This is due to the fact that the fan-out
take a different route via the delegate process than the direct delivery that
bypasses it.

This commit only reverses it for the `invoke_no_result/2|3` API and leaves the
optimisation in for the synchronous `invoke/` API. This means that the message
send ordering you expect between erlang processes still can be violated when
mixing invoke and invoke_no_result invocations. As far as I can see there are
no places where the code relies on this and there are uses of invoke (mgmt db)
that very well could benefit from avoiding the additional copying.

(cherry picked from commit 8804434)

deps/rabbit_common/src/delegate.erl

@@ -169,9 +169,6 @@ demonitor(Ref) when is_reference(Ref) ->
 demonitor({Name, Pid}) ->
     gen_server2:cast(Name, {demonitor, self(), Pid}).
 
-invoke_no_result(Pid, FunOrMFA = {gen_server2, _F, _A}) when is_pid(Pid) ->
-    _ = safe_invoke(Pid, FunOrMFA), %% we don't care about any error
-    ok;
 invoke_no_result(Pid, FunOrMFA) when is_pid(Pid) andalso node(Pid) =:= node() ->
     %% Optimization, avoids calling invoke_no_result/3.
     %%
@@ -192,9 +189,6 @@ invoke_no_result(Pid, FunOrMFA) when is_pid(Pid) ->
     ok;
 invoke_no_result([], _FunOrMFA) -> %% optimisation
     ok;
-invoke_no_result([Pid], FunOrMFA = {gen_server2, _F, _A}) when is_pid(Pid) -> %% optimisation
-    _ = safe_invoke(Pid, FunOrMFA), %% must not die
-    ok;
 invoke_no_result([Pid], FunOrMFA) when node(Pid) =:= node() -> %% optimisation
     _ = safe_invoke(Pid, FunOrMFA), %% must not die
     ok;
@@ -204,9 +198,6 @@ invoke_no_result([Pid], FunOrMFA) ->
                        {invoke, FunOrMFA,
                         maps:from_list([{RemoteNode, [Pid]}])}),
     ok;
-invoke_no_result(Pids, FunOrMFA = {gen_server2, _F, _A}) when is_list(Pids) ->
-    {LocalCallPids, Grouped} = group_local_call_pids_by_node(Pids),
-    invoke_no_result(Pids, FunOrMFA, LocalCallPids, Grouped);
 invoke_no_result(Pids, FunOrMFA) when is_list(Pids) ->
     {LocalPids, Grouped} = group_pids_by_node(Pids),
     invoke_no_result(Pids, FunOrMFA, LocalPids, Grouped).