gh-136438: Make sure test_generated_cases pass with all optimization levels (#136594)

Fix the `test_generated_cases` to work with `-O` or `-OO` flags.
Previously, `test_generated_cases` was catching an `AssertionError` while `Tools/cases_generator/optimizer_generator.py` used an `assert` statement.  This approach semantically incorrect, no one should trying to catch an `AssertionError`!
Now the `assert` statement has been replaced with an explicit `raise ValueError(...)` and the corresponding `self.assertRaisesRegex(AssertionError, ...)` has been updated to catch a `ValueError` instead.

Lib/test/test_generated_cases.py

@@ -2037,7 +2037,7 @@ class TestGeneratedAbstractCases(unittest.TestCase):
         """
         output = """
         """
-        with self.assertRaisesRegex(AssertionError, "All abstract uops"):
+        with self.assertRaisesRegex(ValueError, "All abstract uops"):
             self.run_cases_test(input, input2, output)
 
     def test_validate_uop_input_length_mismatch(self):

Tools/cases_generator/optimizer_generator.py

@@ -398,9 +398,9 @@ def generate_abstract_interpreter(
     out.emit("\n")
     base_uop_names = set([uop.name for uop in base.uops.values()])
     for abstract_uop_name in abstract.uops:
-        assert (
-            abstract_uop_name in base_uop_names
-        ), f"All abstract uops should override base uops, but {abstract_uop_name} is not."
+        if abstract_uop_name not in base_uop_names:
+            raise ValueError(f"All abstract uops should override base uops, "
+                                 "but {abstract_uop_name} is not.")
 
     for uop in base.uops.values():
         override: Uop | None = None