[OpenReg] Strengthen Openreg's execution limits to minimize the waste of computing resources (#161918)

Currently, OpenReg supports Linux, Windows, and OS X, ensuring stability and ease of integration with third-party devices across all three platforms. It also doesn't rely on any other accelerators (such as CUDA or MPS).

Therefore, to minimize computational resource usage, `test_openreg` can be added to certain BLOCKLISTS to prevent its execution, limiting OpenReg's execution to only necessary scenarios.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/161918
Approved by: https://github.com/albanD
ghstack dependencies: #161917

test/cpp_extensions/open_registration_extension/torch_openreg/tests/test_ops.py

@@ -2,18 +2,11 @@
 
 import collections
 import functools
-import unittest
 
 import torch
 from torch.nn.attention import SDPBackend
 from torch.testing._internal.common_nn import NNTestCase
-from torch.testing._internal.common_utils import (
-    run_tests,
-    skipIfTorchDynamo,
-    skipIfXpu,
-    TEST_XPU,
-    TestCase,
-)
+from torch.testing._internal.common_utils import run_tests, skipIfTorchDynamo, TestCase
 
 
 SDPAShape = collections.namedtuple(
@@ -123,7 +116,6 @@ class TestSTUB(TestCase):
 
 
 class TestQuantization(TestCase):
-    @skipIfXpu(msg="missing kernel for openreg")
     def test_quantize(self):
         x = torch.randn(3, 4, 5, dtype=torch.float32, device="openreg")
         quantized_tensor = torch.quantize_per_tensor(x, 0.1, 10, torch.qint8)
@@ -206,7 +198,6 @@ class TestFallback(TestCase):
         self.assertEqual(z_cpu, z[1])
 
 
-@unittest.skipIf(TEST_XPU, "XPU does not support cppextension currently")
 class TestSDPA(NNTestCase):
     @skipIfTorchDynamo()
     def test_fused_sdp_choice_privateuseone(self):