[ONNX] add test images to repo (pytorch#63717)

Summary:
This is better than the status quo:
* Test doesn't download files from the internet -> faster and more
  reliable.
* Test doesn't leave the git working directory dirty.

Rather than using the original images, I've copied some images from
the pytorch/vision repo. This will keep the tests in the two repos
in sync, while avoiding adding new assets to the vision repo.

See pytorch/vision#4176.

Pull Request resolved: pytorch#63717

Reviewed By: janeyx99

Differential Revision: D30466016

Pulled By: malfet

fbshipit-source-id: 2c56d4c11b5c74db1764576bf1c95ce4ae714574

Author: garymm

test/onnx/assets/grace_hopper_517x606.jpg

@@ -496,35 +496,20 @@ def run_word_language_model(self, model_name):
         # Only support CPU version, since tracer is not working in GPU RNN.
         self.run_test(model, (x, model.hidden))
 
-    def get_image_from_url(self, url, size=(300, 200)):
+    def get_image(self, rel_path: str, size: Tuple[int, int]) -> torch.Tensor:
         import os
-        from urllib.parse import urlsplit
-        from urllib import request
         from PIL import Image
         from torchvision import transforms
-        from torch._utils_internal import get_writable_path
 
-        filename = os.path.basename(urlsplit(url)[2])
-        data_dir = get_writable_path(os.path.join(os.path.dirname(__file__)))
-        path = os.path.join(data_dir, filename)
-        data = request.urlopen(url, timeout=15).read()
-        with open(path, "wb") as f:
-            f.write(data)
-        image = Image.open(path).convert("RGB")
+        data_dir = os.path.join(os.path.dirname(__file__), "assets")
+        path = os.path.join(data_dir, *rel_path.split("/"))
+        image = Image.open(path).convert("RGB").resize(size, Image.BILINEAR)
 
-        image = image.resize(size, Image.BILINEAR)
+        return transforms.ToTensor()(image)
 
-        to_tensor = transforms.ToTensor()
-        return to_tensor(image)
-
-    def get_test_images(self):
-        image_url = "http://farm3.staticflickr.com/2469/3915380994_2e611b1779_z.jpg"
-        image = self.get_image_from_url(url=image_url, size=(100, 320))
-
-        image_url2 = "https://pytorch.org/tutorials/_static/img/tv_tutorial/tv_image05.png"
-        image2 = self.get_image_from_url(url=image_url2, size=(250, 380))
-
-        return [image], [image2]
+    def get_test_images(self) -> Tuple[List[torch.Tensor], List[torch.Tensor]]:
+        return ([self.get_image("grace_hopper_517x606.jpg", (100, 320))],
+                [self.get_image("rgb_pytorch.png", (250, 380))])
 
     @skipIfUnsupportedMinOpsetVersion(11)
     @disableScriptTest()  # Faster RCNN model is not scriptable