Remove _Py_ResetReferences. Fixes bug #529750 "Circular reference makes

Py_Init crash".  refchain cannot be cleared because objects can live across
Py_Finalize() and Py_Initialize() if they are kept alive by circular
references.

Include/object.h

@@ -559,7 +559,6 @@ PyAPI_FUNC(void) _Py_NewReference(PyObject *);
 PyAPI_FUNC(void) _Py_ForgetReference(PyObject *);
 PyAPI_FUNC(void) _Py_Dealloc(PyObject *);
 PyAPI_FUNC(void) _Py_PrintReferences(FILE *);
-PyAPI_FUNC(void) _Py_ResetReferences(void);
 
 #else
 /* Without Py_TRACE_REFS, there's little enough to do that we expand code

Objects/object.c

@@ -1908,13 +1908,6 @@ _Py_ReadyTypes(void)
 
 static PyObject refchain = {&refchain, &refchain};
 
-void
-_Py_ResetReferences(void)
-{
-	refchain._ob_prev = refchain._ob_next = &refchain;
-	_Py_RefTotal = 0;
-}
-
 void
 _Py_NewReference(PyObject *op)
 {

Python/pythonrun.c

@@ -277,10 +277,6 @@ Py_Finalize(void)
 #endif
 
 	call_ll_exitfuncs();
-
-#ifdef Py_TRACE_REFS
-	_Py_ResetReferences();
-#endif /* Py_TRACE_REFS */
 }
 
 /* Create and initialize a new interpreter and thread, and return the