bpo-32388: Remove cross-version binary compatibility requirement in tp_flags (GH-4944)

It is now allowed to add new fields at the end of the PyTypeObject struct without having to allocate a dedicated compatibility flag in tp_flags.

This will reduce the risk of running out of bits in the 32-bit tp_flags value.
diff --git a/Objects/genobject.c b/Objects/genobject.c
index e2def38..0d0a02d 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -742,8 +742,7 @@
     PyObject_GenericGetAttr,                    /* tp_getattro */
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_HAVE_FINALIZE,               /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,    /* tp_flags */
     0,                                          /* tp_doc */
     (traverseproc)gen_traverse,                 /* tp_traverse */
     0,                                          /* tp_clear */
@@ -997,8 +996,7 @@
     PyObject_GenericGetAttr,                    /* tp_getattro */
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_HAVE_FINALIZE,               /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,    /* tp_flags */
     0,                                          /* tp_doc */
     (traverseproc)gen_traverse,                 /* tp_traverse */
     0,                                          /* tp_clear */
@@ -1394,8 +1392,7 @@
     PyObject_GenericGetAttr,                    /* tp_getattro */
     0,                                          /* tp_setattro */
     0,                                          /* tp_as_buffer */
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-        Py_TPFLAGS_HAVE_FINALIZE,               /* tp_flags */
+    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,    /* tp_flags */
     0,                                          /* tp_doc */
     (traverseproc)async_gen_traverse,           /* tp_traverse */
     0,                                          /* tp_clear */