Revert "ENH: More uint types for torch"

This reverts commit c787bea.

PyTorch support for unsigned ints is patchy, as of pytorch 2.6 at least.
See data-apis#253 (comment)
for a discussion.

Author: ev-br

array_api_compat/torch/_aliases.py

@@ -31,12 +31,6 @@
     torch.int32,
     torch.int64,
 }
-try:
-    # torch >=2.3
-    _int_dtypes |= {torch.uint16, torch.uint32, torch.uint64}
-except AttributeError:
-    pass
-
 
 _array_api_dtypes = {
     torch.bool,

torch-xfails.txt

@@ -8,11 +8,23 @@ array_api_tests/test_array_object.py::test_getitem
 array_api_tests/test_array_object.py::test_setitem
 # Masking doesn't suport 0 dimensions in the mask
 array_api_tests/test_array_object.py::test_getitem_masking
+# torch doesn't have uint dtypes other than uint8
+array_api_tests/test_array_object.py::test_scalar_casting[__int__(uint16)]
+array_api_tests/test_array_object.py::test_scalar_casting[__int__(uint32)]
+array_api_tests/test_array_object.py::test_scalar_casting[__int__(uint64)]
+array_api_tests/test_array_object.py::test_scalar_casting[__index__(uint16)]
+array_api_tests/test_array_object.py::test_scalar_casting[__index__(uint32)]
+array_api_tests/test_array_object.py::test_scalar_casting[__index__(uint64)]
 
 # Overflow error from large inputs
 array_api_tests/test_creation_functions.py::test_arange
 # pytorch linspace bug (should be fixed in torch 2.0)
 
+# torch doesn't have higher uint dtypes
+array_api_tests/test_data_type_functions.py::test_iinfo[uint16]
+array_api_tests/test_data_type_functions.py::test_iinfo[uint32]
+array_api_tests/test_data_type_functions.py::test_iinfo[uint64]
+
 # We cannot wrap the tensor object
 array_api_tests/test_has_names.py::test_has_names[array_method-__array_namespace__]
 array_api_tests/test_has_names.py::test_has_names[array_method-to_device]