Maybe reduce flakiness of the exchange_SUITE

Author: HoloRin

deps/rabbitmq_federation/BUILD.bazel

@@ -82,6 +82,7 @@ suites = [
             ":rabbit_federation_test_util",
         ],
         flaky = True,
+        shard_count = 6,
     ),
     rabbitmq_integration_suite(
         PACKAGE,

deps/rabbitmq_federation/test/exchange_SUITE.erl

@@ -526,6 +526,7 @@ restart_upstream(Config) ->
     Qgoes = bind_queue(Downstream, <<"hare.downstream">>, <<"goes">>),
 
     rabbit_ct_client_helpers:close_channels_and_connection(Config, Hare),
+    timer:sleep(3000),
     rabbit_ct_broker_helpers:stop_node(Config, Hare),
 
     Qcomes = bind_queue(Downstream, <<"hare.downstream">>, <<"comes">>),