Porting fix from CL- https://critique.corp.google.com/#review/210573936

src/core/ext/filters/max_age/max_age_filter.cc

@@ -430,7 +430,7 @@ static grpc_error* init_channel_elem(grpc_channel_element* elem,
                                    : DEFAULT_MAX_CONNECTION_IDLE_MS;
   chand->idle_state = MAX_IDLE_STATE_INIT;
   gpr_atm_no_barrier_store(&chand->last_enter_idle_time_millis,
-                           GRPC_MILLIS_INF_PAST);
+                           GPR_ATM_MIN);
   for (size_t i = 0; i < args->channel_args->num_args; ++i) {
     if (0 == strcmp(args->channel_args->args[i].key,
                     GRPC_ARG_MAX_CONNECTION_AGE_MS)) {