TEST/UCP/DEVICE: Use flush_ep() to ensure endpoint wireup

Author: michal-shalev

test/gtest/ucp/test_ucp_device.cc

@@ -8,7 +8,6 @@
 #include <ucp/ucp_test.h>
 
 #include <ucp/api/device/ucp_device_types.h>
-#include <ucp/core/ucp_ep.h>
 
 #include <common/cuda.h>
 #include "cuda/test_kernels.h"