Remove torchvision.io from test_utils.py (#3092)

For now this simplifies a few things for fbcode integration. We can add this back in the future

Author: fmassa

test/test_utils.py

@@ -1,3 +1,4 @@
+import numpy as np
 import os
 import sys
 import tempfile
@@ -6,7 +7,6 @@
 import unittest
 from io import BytesIO
 import torchvision.transforms.functional as F
-from torchvision.io.image import read_image, write_png
 from PIL import Image
 
 
@@ -90,9 +90,10 @@ def test_draw_boxes(self):
 
         path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "assets", "fakedata", "draw_boxes_util.png")
         if not os.path.exists(path):
-            write_png(result, path)
+            res = Image.fromarray(result.permute(1, 2, 0).contiguous().numpy())
+            res.save(path)
 
-        expected = read_image(path)
+        expected = torch.as_tensor(np.array(Image.open(path))).permute(2, 0, 1)
         self.assertTrue(torch.equal(result, expected))