Speed up shovel start and cleanup

The filtering was incorrect, so we ended up trying to delete
all existing shovels. Running shovels would reject the attempt,
so things generally worked as expected, but this redundant work
was quite costly.

In a test with 1000 shovels, this change speeds up a definition import
from a few minutes to a few seconds.

Fixes #9714
Fixes #8364

Author: mkuratczyk

deps/rabbitmq_shovel/src/rabbit_shovel_dyn_worker_sup_sup.erl

@@ -84,7 +84,8 @@ stop_child({VHost, ShovelName} = Name) ->
 
 cleanup_specs() ->
     SpecsSet = sets:from_list([element(2, element(1, S)) || S <- mirrored_supervisor:which_children(?SUPERVISOR)]),
-    ParamsSet = sets:from_list(rabbit_runtime_parameters:list_component(<<"shovel">>)),
+    ParamsSet = sets:from_list([ {proplists:get_value(vhost, S), proplists:get_value(name, S)}
+                                 || S <- rabbit_runtime_parameters:list_component(<<"shovel">>) ]),
     F = fun(Name, ok) ->
             _ = mirrored_supervisor:delete_child(?SUPERVISOR, id(Name)),
             ok