[3.12] gh-127599: Fix _Py_RefcntAdd missing calls to _Py_INCREF_STAT_INC/_Py_INCREF_IMMORTAL_STAT_INC (GH-127717) (#128712)

Previously, `_Py_RefcntAdd` hasn't called
`_Py_INCREF_STAT_INC/_Py_INCREF_IMMORTAL_STAT_INC` which is incorrect.

Now it has been fixed.
(cherry picked from commit ab05beb8cea62636bd86f6f7cf1a82d7efca7162)