[BE] bump optree version to 0.12.1 (#130139)

0.12.0 Major Updates:

- Add context manager to temporarily set the dictionary sorting mode
- Add accessor APIs
- Use `stable` tag for `pybind11` for Python 3.13 support
- Fix potential segmentation fault for pickling support

0.12.1 Updates:

- Fix warning regression during import when launch with strict warning filters

Closes #130155
Pull Request resolved: https://github.com/pytorch/pytorch/pull/130139
Approved by: https://github.com/zou3519

test/test_testing.py

@@ -2216,7 +2216,7 @@ class TestImports(TestCase):
     @classmethod
     def _check_python_output(cls, program) -> str:
         return subprocess.check_output(
-            [sys.executable, "-W", "all", "-c", program],
+            [sys.executable, "-W", "always", "-c", program],
             stderr=subprocess.STDOUT,
             # On Windows, opening the subprocess with the default CWD makes `import torch`
             # fail, so just set CWD to this script's directory