Resolve stride mismatch in UNet's ResNet to support Torch DDP (#11098)

Modify UNet's ResNet implementation to resolve stride mismatch in Torch's DDP

Author: jinc7461

src/diffusers/models/resnet.py

@@ -366,7 +366,7 @@ def forward(self, input_tensor: torch.Tensor, temb: torch.Tensor, *args, **kwarg
         hidden_states = self.conv2(hidden_states)
 
         if self.conv_shortcut is not None:
-            input_tensor = self.conv_shortcut(input_tensor)
+            input_tensor = self.conv_shortcut(input_tensor.contiguous())
 
         output_tensor = (input_tensor + hidden_states) / self.output_scale_factor