test error tests.test_detection_coco_metrics

[wyli]

Describe the bug

the issue randomly occurs, for example https://github.com/Project-MONAI/MONAI/runs/6916583038?check_suite_focus=true

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FAIL: test_coco_run (tests.test_detection_coco_metrics.TestCOCOMetrics)
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Traceback (most recent call last):
  File "/home/runner/work/MONAI/MONAI/tests/test_detection_coco_metrics.py", line 62, in test_coco_run
    np.testing.assert_array_less([-0.01], [sum(val_epoch_metric_dict.values())])
  File "/opt/hostedtoolcache/Python/3.7.13/x64/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 1131, in assert_array_less
    equal_inf=False)
  File "/opt/hostedtoolcache/Python/3.7.13/x64/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 844, in assert_array_compare
    raise AssertionError(msg)
AssertionError: 
Arrays are not less-ordered
Mismatched elements: 1 / 1 (100%)
Max absolute difference: 3.17686152
Max relative difference: 0.99686212
 x: array([-0.01])
 y: array([-3.186862])
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