bpo-43268: _Py_IsMainInterpreter() now expects interp (GH-24577)

The _Py_IsMainInterpreter() function now expects interp rather than
tstate.
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 240e92a..c0b4ce0 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -5719,7 +5719,7 @@ _PyLong_Init(PyThreadState *tstate)
         tstate->interp->small_ints[i] = v;
     }
 
-    if (_Py_IsMainInterpreter(tstate)) {
+    if (_Py_IsMainInterpreter(tstate->interp)) {
         /* initialize int_info */
         if (Int_InfoType.tp_name == NULL) {
             if (PyStructSequence_InitType2(&Int_InfoType, &int_info_desc) < 0) {
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 3498f0d..9dbb7be 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -286,7 +286,7 @@ void
 _PyType_Fini(PyThreadState *tstate)
 {
     _PyType_ClearCache(&tstate->interp->type_cache);
-    if (_Py_IsMainInterpreter(tstate)) {
+    if (_Py_IsMainInterpreter(tstate->interp)) {
         clear_slotdefs();
     }
 }
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 64fd408..498f393 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -15701,7 +15701,7 @@ _PyUnicode_Init(PyThreadState *tstate)
         return _PyStatus_NO_MEMORY();
     }
 
-    if (_Py_IsMainInterpreter(tstate)) {
+    if (_Py_IsMainInterpreter(tstate->interp)) {
         /* initialize the linebreak bloom filter */
         bloom_linebreak = make_bloom_mask(
             PyUnicode_2BYTE_KIND, linebreak,