In channelpadding tests that touch libevent, call event_reinit().

This is necessary to avoid crashes and test failures on kevent-based
systems.

Fixes bug 22209; bug not in any released Tor.

src/test/test_channelpadding.c

@@ -258,6 +258,9 @@ test_channelpadding_timers(void *arg)
   channelpadding_decision_t decision;
   channel_t *chans[CHANNELS_TO_TEST];
   (void)arg;
+
+  tor_libevent_postfork();
+
   connection_array = smartlist_new();
 
   monotime_init();
@@ -349,6 +352,8 @@ test_channelpadding_consensus(void *arg)
   int64_t val;
   (void)arg;
 
+  tor_libevent_postfork();
+
   /*
    * Params tested:
    *   nf_pad_before_usage
@@ -723,6 +728,8 @@ test_channelpadding_decide_to_pad_channel(void *arg)
   connection_array = smartlist_new();
   (void)arg;
 
+  tor_libevent_postfork();
+
   monotime_init();
   timers_initialize();
   setup_full_capture_of_logs(LOG_WARN);