bpo-43268: Pass interp rather than tstate to internal functions (GH-24580)

Pass the current interpreter (interp) rather than the current Python
thread state (tstate) to internal functions which only use the
interpreter.

Modified functions:

* _PyXXX_Fini() and _PyXXX_ClearFreeList() functions
* _PyEval_SignalAsyncExc(), make_pending_calls()
* _PySys_GetObject(), sys_set_object(), sys_set_object_id(), sys_set_object_str()
* should_audit(), set_flags_from_config(), make_flags()
* _PyAtExit_Call()
* init_stdio_encoding()
* etc.
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 62cec9a..88e2287 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -2529,9 +2529,9 @@ SimpleExtendsException(PyExc_Warning, ResourceWarning,
 #endif /* MS_WINDOWS */
 
 PyStatus
-_PyExc_Init(PyThreadState *tstate)
+_PyExc_Init(PyInterpreterState *interp)
 {
-    struct _Py_exc_state *state = &tstate->interp->exc_state;
+    struct _Py_exc_state *state = &interp->exc_state;
 
 #define PRE_INIT(TYPE) \
     if (!(_PyExc_ ## TYPE.tp_flags & Py_TPFLAGS_READY)) { \
@@ -2766,9 +2766,9 @@ _PyBuiltins_AddExceptions(PyObject *bltinmod)
 }
 
 void
-_PyExc_Fini(PyThreadState *tstate)
+_PyExc_Fini(PyInterpreterState *interp)
 {
-    struct _Py_exc_state *state = &tstate->interp->exc_state;
+    struct _Py_exc_state *state = &interp->exc_state;
     free_preallocated_memerrors(state);
     Py_CLEAR(state->errnomap);
 }