Revert "[Dynamo] Check for __bool__ attribute before accessing it (#120943)"

This reverts commit dd7aeedb72f8a96d0f168308292e0d41c095f01b.

Reverted https://github.com/pytorch/pytorch/pull/120943 on behalf of https://github.com/DanilBaibak due to Broken trunk ([comment](https://github.com/pytorch/pytorch/pull/120943#issuecomment-2063098295))

torch/_dynamo/symbolic_convert.py

@@ -409,14 +409,10 @@ def generic_jump(truth_fn: typing.Callable[[object], bool], push: bool):
                     self.push(value)
                 self.jump(inst)
         elif isinstance(value, UserDefinedObjectVariable):
-            x = None
-            has_bool = value.call_hasattr(self, "__bool__")
-            if has_bool.is_python_constant() and has_bool.as_python_constant():
-                x = value.var_getattr(self, "__bool__")
-            else:
-                has_len = value.call_hasattr(self, "__len__")
-                if has_len.is_python_constant() and has_len.as_python_constant():
-                    x = value.var_getattr(self, "__len__")
+            x = value.var_getattr(self, "__bool__")
+            # if __bool__ is missing, trying __len__ to infer a truth value.
+            if isinstance(x, GetAttrVariable):
+                x = value.var_getattr(self, "__len__")
 
             # __bool__ or __len__ is function
             if isinstance(x, UserMethodVariable):