[lldb] Fix D114722 for python<=3.6

_Py_IsFinalizing was called _Py_Finalizing back then (and it was a
variable instead of a function).

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

@@ -69,6 +69,28 @@ Expected<std::string> python::As<std::string>(Expected<PythonObject> &&obj) {
   return std::string(utf8.get());
 }
 
+static bool python_is_finalizing() {
+#if PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION < 7
+  return _Py_Finalizing != nullptr;
+#else
+  return _Py_IsFinalizing();
+#endif
+}
+
+void PythonObject::Reset() {
+  if (m_py_obj && Py_IsInitialized()) {
+    if (python_is_finalizing()) {
+      // Leak m_py_obj rather than crashing the process.
+      // https://docs.python.org/3/c-api/init.html#c.PyGILState_Ensure
+    } else {
+      PyGILState_STATE state = PyGILState_Ensure();
+      Py_DECREF(m_py_obj);
+      PyGILState_Release(state);
+    }
+  }
+  m_py_obj = nullptr;
+}
+
 Expected<long long> PythonObject::AsLongLong() const {
   if (!m_py_obj)
     return nullDeref();