[Polish utils/pybind.h] Delete p_tensor_type in pybind.h (#51715)

paddle/utils/pybind.cc

@@ -21,8 +21,8 @@ DECLARE_string(tensor_operants_mode);
 namespace paddle {
 namespace pybind {
 
-PyTypeObject* p_tensor_type;
-PyTypeObject* p_string_tensor_type;
+PyTypeObject* p_tensor_type = nullptr;
+PyTypeObject* p_string_tensor_type = nullptr;
 
 bool PyCheckTensor(PyObject* obj) {
   if (!p_tensor_type) {

paddle/utils/pybind.h

@@ -24,8 +24,6 @@ namespace py = pybind11;
 namespace paddle {
 namespace pybind {
 
-extern PyTypeObject* p_tensor_type;
-
 typedef struct {
   PyObject_HEAD paddle::Tensor tensor;
   // Weak references