update to torch nightly

Author: rusty1s

test/utils.py

@@ -6,6 +6,8 @@
 dtypes.remove(torch.half)
 dtypes.remove(torch.short)  # PyTorch scatter does not work on short types.
 dtypes.remove(torch.bool)
+if torch.bfloat16 in dtypes:
+    dtypes.remove(torch.bfloat16)
 
 grad_dtypes = [torch.float, torch.double]