[lldb] Adapt code to Python 3.13 (llvm#70445)

1. Remove usage of PyEval_ThreadsInitialized and PyEval_InitThreads

Both of these functions were removed in Python 3.13 [1] after being
deprecated since Python 3.9.

According to "What's new in Python 3.13" document [1]:

    Since Python 3.7, Py_Initialize() always creates the GIL: calling
    PyEval_InitThreads() did nothing and PyEval_ThreadsInitialized()
    always returned non-zero.

2. Replace _Py_IsFinalizing() with Py_IsFinalizing().

[1] https://docs.python.org/3.13/whatsnew/3.13.html

(cherry picked from commit b2929be)

Author: tuliom

lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp

@@ -72,7 +72,9 @@ Expected<std::string> python::As<std::string>(Expected<PythonObject> &&obj) {
 }
 
 static bool python_is_finalizing() {
-#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 7
+#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION >= 13) || (PY_MAJOR_VERSION > 3)
+  return Py_IsFinalizing();
+#elif PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 7
   return _Py_Finalizing != nullptr;
 #else
   return _Py_IsFinalizing();

lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp

@@ -176,18 +176,27 @@ struct InitializePythonRAII {
       return;
 #endif
 
+// `PyEval_ThreadsInitialized` was deprecated in Python 3.9 and removed in
+// Python 3.13. It has been returning `true` always since Python 3.7.
+#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 9) || (PY_MAJOR_VERSION < 3)
     if (PyEval_ThreadsInitialized()) {
+#endif
       Log *log = GetLog(LLDBLog::Script);
 
       m_was_already_initialized = true;
       m_gil_state = PyGILState_Ensure();
       LLDB_LOGV(log, "Ensured PyGILState. Previous state = {0}locked\n",
                 m_gil_state == PyGILState_UNLOCKED ? "un" : "");
+
+// `PyEval_InitThreads` was deprecated in Python 3.9 and removed in
+// Python 3.13.
+#if (PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 9) || (PY_MAJOR_VERSION < 3)
       return;
     }
 
     // InitThreads acquires the GIL if it hasn't been called before.
     PyEval_InitThreads();
+#endif
   }
 
   PyGILState_STATE m_gil_state = PyGILState_UNLOCKED;