Update on "[ExecuTorch] Arm Ethos: Do not depend on torch.testing._internal "

This can cuase issues with `disable_global_flags` and internal state of the library, this is something which is set when importing this.

Differential Revision: [D70402061](https://our.internmc.facebook.com/intern/diff/D70402061/)

[ghstack-poisoned]

Author: digantdesai

backends/arm/test/passes/test_rescale_pass.py

@@ -14,8 +14,6 @@
 from executorch.backends.arm.test.tester.arm_tester import ArmTester
 from parameterized import parameterized
 
-class OpCheckError(Exception):
-    pass
 
 def test_rescale_op():
     sample_inputs = [
@@ -65,7 +63,7 @@ def test_nonzero_zp_for_int32():
         ),
     ]
     for sample_input in sample_inputs:
-        with pytest.raises(OpCheckError):
+        with pytest.raises(Exception, match="OpCheckError"):
             torch.library.opcheck(torch.ops.tosa._rescale, sample_input)
 
 
@@ -88,7 +86,7 @@ def test_zp_outside_range():
         ),
     ]
     for sample_input in sample_inputs:
-        with pytest.raises(OpCheckError):
+        with pytest.raises(Exception, match="OpCheckError"):
             torch.library.opcheck(torch.ops.tosa._rescale, sample_input)