test: fix flaky test

The cause was that the call `sys:terminate/2` was timing out...

`exit/2` doens't always work:

```
 2023-11-22 19:14:40.974
killed async workers

Error: -22T19:14:40.974563+00:00 [error] crasher: initial call: gun:proc_lib_hack/5, pid: <0.15908.7>, registered_name: [], exit: {{{owner_gone,killed},[{gun,owner_gone,1,[{file,"gun.erl"},{line,970}]},{gun,proc_lib_hack,5,[{file,"gun.erl"},{line,649}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]},[{gun,proc_lib_hack,5,[{file,"gun.erl"},{line,654}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]}, ancestors: [gun_sup,<0.15387.7>], message_queue_len: 0, messages: [], links: [<0.15388.7>], dictionary: [], trap_exit: false, status: running, heap_size: 987, stack_size: 28, reductions: 1822; neighbours:
Error: -22T19:14:40.998051+00:00 [error] Supervisor: {local,gun_sup}. Context: child_terminated. Reason: {{owner_gone,killed},[{gun,owner_gone,1,[{file,"gun.erl"},{line,970}]},{gun,proc_lib_hack,5,[{file,"gun.erl"},{line,649}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]}. Offender: id=gun,pid=<0.15908.7>.
2023-11-22T19:15:41.088752+00:00 [critical] Run stage failed: error:{badmatch,{timeout,#{expected_remaining => 1,mailbox => {messages,[]},msgs_so_far => []}}}, Stacktrace: [{emqx_bridge_gcp_pubsub_consumer_SUITE,'-t_async_worker_death_mid_pull/1-fun-17-',3,[{file,"/emqx/apps/emqx_bridge_gcp_pubsub/test/emqx_bridge_gcp_pubsub_consumer_SUITE.erl"},{line,1576}]},{emqx_bridge_gcp_pubsub_consumer_SUITE,t_async_worker_death_mid_pull,1,[{file,"/emqx/apps/emqx_bridge_gcp_pubsub/test/emqx_bridge_gcp_pubsub_consumer_SUITE.erl"},{line,1505}]}], Trace dump: "/emqx/_build/test/logs/ct_run.test@127.0.0.1.2023-11-22_19.14.27/snabbkaffe/1700680540975786370.log", mfa: undefined
Error: -22T19:15:46.095702+00:00 [error] crasher: initial call: gun:proc_lib_hack/5, pid: <0.15934.7>, registered_name: [], exit: {{{owner_gone,killed},[{gun,owner_gone,1,[{file,"gun.erl"},{line,970}]},{gun,proc_lib_hack,5,[{file,"gun.erl"},{line,649}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]},[{gun,proc_lib_hack,5,[{file,"gun.erl"},{line,654}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]}, ancestors: [gun_sup,<0.15387.7>], message_queue_len: 0, messages: [], links: [<0.15388.7>], dictionary: [], trap_exit: false, status: running, heap_size: 610, stack_size: 28, reductions: 1471; neighbours:
Error: -22T19:15:46.095192+00:00 [error] Supervisor: {local,ehttpc_sup}. Context: shutdown_error. Reason: killed. Offender: id={ehttpc_pool_sup,<<98,114,105,100,103,101,58,103,99,112,95,112,117,98,115,117,98,95,99,111,110,115,117,109,101,114,58,116,95,97,115,121,110,99,95,119,111,114,107,101,114,95,100,101,97,116,104,95,109,105,100,95,112,117,108,108,45,53,55,54,52,54,48,55,53,50,51,48,51,52,50,50,55,53,49>>},pid=<0.15903.7>.
Error: -22T19:15:46.095470+00:00 [error] Supervisor: {<0.15906.7>,ehttpc_worker_sup}. Context: shutdown_error. Reason: killed. Offender: id={worker,1},pid=<0.15924.7>.
Error: -22T19:15:46.096762+00:00 [error] Supervisor: {local,gun_sup}. Context: child_terminated. Reason: {{owner_gone,killed},[{gun,owner_gone,1,[{file,"gun.erl"},{line,970}]},{gun,proc_lib_hack,5,[{file,"gun.erl"},{line,649}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]}. Offender: id=gun,pid=<0.15934.7>.
Warning: 2T19:15:46.098278+00:00 [warning] msg: remove_local_resource_failed, mfa: emqx_resource:remove_local/1(362), error: {error,timeout}, resource_id: <<"bridge:gcp_pubsub_consumer:t_async_worker_death_mid_pull-576460752303422751">>
Error: -22T19:15:46.149090+00:00 [error] Generic server <0.15904.7> terminating. Reason: killed. Last message: {'EXIT',<0.15903.7>,killed}. State: {state,<<"bridge:gcp_pubsub_consumer:t_async_worker_death_mid_pull-576460752303422751">>,1,random}.
Error: -22T19:15:46.149525+00:00 [error] crasher: initial call: ehttpc_pool:init/1, pid: <0.15904.7>, registered_name: [], exit: {killed,[{gen_server,decode_msg,9,[{file,"gen_server.erl"},{line,909}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]}, ancestors: [<0.15903.7>,ehttpc_sup,<0.15731.7>], message_queue_len: 0, messages: [], links: [], dictionary: [], trap_exit: true, status: running, heap_size: 376, stack_size: 28, reductions: 3428; neighbours:
```

apps/emqx_bridge_gcp_pubsub/test/emqx_bridge_gcp_pubsub_consumer_SUITE.erl

@@ -34,16 +34,22 @@ init_per_suite(Config) ->
     emqx_common_test_helpers:reset_proxy(ProxyHost, ProxyPort),
     case emqx_common_test_helpers:is_tcp_server_available(GCPEmulatorHost, GCPEmulatorPort) of
         true ->
-            ok = emqx_common_test_helpers:start_apps([emqx_conf]),
-            ok = emqx_connector_test_helpers:start_apps([
-                emqx_resource, emqx_bridge, emqx_rule_engine
-            ]),
-            {ok, _} = application:ensure_all_started(emqx_connector),
+            Apps = emqx_cth_suite:start(
+                [
+                    emqx,
+                    emqx_conf,
+                    emqx_bridge_gcp_pubsub,
+                    emqx_bridge,
+                    emqx_rule_engine
+                ],
+                #{work_dir => emqx_cth_suite:work_dir(Config)}
+            ),
             emqx_mgmt_api_test_util:init_suite(),
             HostPort = GCPEmulatorHost ++ ":" ++ GCPEmulatorPortStr,
             true = os:putenv("PUBSUB_EMULATOR_HOST", HostPort),
             Client = start_control_client(),
             [
+                {apps, Apps},
                 {proxy_name, ProxyName},
                 {proxy_host, ProxyHost},
                 {proxy_port, ProxyPort},
@@ -62,12 +68,11 @@ init_per_suite(Config) ->
     end.
 
 end_per_suite(Config) ->
+    Apps = ?config(apps, Config),
     Client = ?config(client, Config),
     stop_control_client(Client),
     emqx_mgmt_api_test_util:end_suite(),
-    ok = emqx_common_test_helpers:stop_apps([emqx_conf]),
-    ok = emqx_connector_test_helpers:stop_apps([emqx_bridge, emqx_resource, emqx_rule_engine]),
-    _ = application:stop(emqx_connector),
+    emqx_cth_suite:stop(Apps),
     os:unsetenv("PUBSUB_EMULATOR_HOST"),
     ok.
 
@@ -1514,7 +1519,7 @@ t_async_worker_death_mid_pull(Config) ->
                 #{?snk_kind := gcp_pubsub_consumer_worker_reply_delegator}
             ),
             spawn_link(fun() ->
-                ct:pal("will kill async worker"),
+                ct:pal("will kill async workers"),
                 ?tp_span(
                     kill_async_worker,
                     #{},
@@ -1530,11 +1535,12 @@ t_async_worker_death_mid_pull(Config) ->
                             fun(AsyncWorkerPid) ->
                                 Ref = monitor(process, AsyncWorkerPid),
                                 ct:pal("killing pid ~p", [AsyncWorkerPid]),
-                                sys:terminate(AsyncWorkerPid, die),
+                                sys:terminate(AsyncWorkerPid, die, 20_000),
                                 receive
                                     {'DOWN', Ref, process, AsyncWorkerPid, _} ->
+                                        ct:pal("killed pid ~p", [AsyncWorkerPid]),
                                         ok
-                                after 500 -> ct:fail("async worker didn't die")
+                                after 500 -> ct:fail("async worker ~p didn't die", [AsyncWorkerPid])
                                 end,
                                 ok
                             end,
@@ -1544,7 +1550,7 @@ t_async_worker_death_mid_pull(Config) ->
                         ok
                     end
                 ),
-                ct:pal("killed async worker")
+                ct:pal("killed async workers")
             end),
 
             ?assertMatch(