Support record_stream in dispatch mode (#99529)

Summary:
Issuing a `t.record_stream(s)` call while a `TorchDispatchMode` is active was throwing because PyTorch was unable to convert a c10::Stream back to a Python object. It's now fixed.

Fixes https://github.com/pytorch/pytorch/issues/94403

Test Plan: Added a unit test

Differential Revision: D45117566

Pull Request resolved: https://github.com/pytorch/pytorch/pull/99529
Approved by: https://github.com/albanD

torchgen/api/python.py

@@ -1133,6 +1133,7 @@ SUPPORTED_RETURN_TYPES = {
     "double",
     "at::IntArrayRef",
     "at::ScalarType",
+    "at::Stream",
 }