Allow selection of debug build interpreters (#11520)

Extends the `PythonVariant` logic to support interpreters with the debug
flag enabled.

crates/uv-python/python/get_interpreter_info.py

@@ -654,6 +654,8 @@ def main() -> None:
         # The `t` abiflag for freethreading Python.
         # https://peps.python.org/pep-0703/#build-configuration-changes
         "gil_disabled": bool(sysconfig.get_config_var("Py_GIL_DISABLED")),
+        # https://docs.python.org/3/using/configure.html#debug-build
+        "debug_enabled": bool(sysconfig.get_config_var("Py_DEBUG")),
         # Determine if the interpreter is 32-bit or 64-bit.
         # https://github.com/python/cpython/blob/b228655c227b2ca298a8ffac44d14ce3d22f6faa/Lib/venv/__init__.py#L136
         "pointer_size": "64" if sys.maxsize > 2**32 else "32",