mimic tp_hash handling (#181328)

Summary:
Add user-facing hash() / __hash__() support to torch.compile by implementing CPython's PyObject_Hash dispatch on Dynamo's VariableTracker hierarchy.

- Add hash_impl(self, tx) -> (int, bool) slot on each VT subclass, mirroring CPython's tp_hash. The bool tracks whether the hash is "fake" (identity-based on a sourceless object).
- Add generic_hash / generic_hash_impl dispatch in object_protocol.py, call_hash in builtin.py, and __hash__ routing in call_method.
- Simplify HashableTracker to delegate to generic_hash_impl instead of the old is_python_hashable() / get_python_hash() per-VT methods (removed from all VTs).
- UserDefinedObjectVariable.hash_impl walks the MRO to trace Python __hash__, call known-safe C hashes, or graph-break on unknown C tp_hash with a hint to use allow_c_hash().
- Non-constant __hash__ returns are handled for FakeIdVariable (propagates is_fake) and SymNodeVariable (specializes via evaluate_expr()).
- Add torch._dynamo.allow_c_hash(tp) API for registering C extension types whose tp_hash is safe to call at trace time. Built-in allowlist covers datetime, decimal.Decimal, and re.Pattern.

X-link: pytorch/pytorch#181328
Approved by: https://github.com/anijain2305

Reviewed By: huydhn

Differential Revision: D104082788

fbshipit-source-id: 1d74340b3dbafac698c8342e0a18d6ef24e8fc40

Author: williamwen42

userbenchmark/dynamo/dynamobench/_dynamo/utils.py

@@ -5502,27 +5502,6 @@ def is_pybind11_enum_member(value: Any) -> bool:
     return name is not None and members.get(name) is value
 
 
-def raise_on_overridden_hash(obj: Any, vt: VariableTracker) -> None:
-    from . import graph_break_hints
-    from .exc import unimplemented
-
-    is_overridden = type(obj).__dict__.get("__hash__", False)
-
-    if is_overridden and is_pybind11_enum_member(obj):
-        return
-
-    if is_overridden:
-        unimplemented(
-            gb_type="User-defined object with overridden __hash__",
-            context=f"hashing object of type={type(obj)} and variable tracker {vt}",
-            explanation=f"Found a user-defined object {vt} with overridden __hash__ when attempting to hash it",
-            hints=[
-                "Dynamo does not support hashing user-defined objects with overridden __hash__",
-                *graph_break_hints.SUPPORTABLE,
-            ],
-        )
-
-
 def _make_inlined(
     tx: InstructionTranslator, f: Callable[..., Any]
 ) -> Callable[..., VariableTracker]: