* Fix fence(IoU) = 0 when training on PascalContextDataset59;
* Add a test case in test_metrics() of tests/test_metrics.py to test the bug caused by torch.histc;
* Update tests/test_metrics.py
Co-authored-by: Jerry Jiarui XU <xvjiarui0826@gmail.com>
Co-authored-by: Jerry Jiarui XU <xvjiarui0826@gmail.com>