Revert "pythongh-111089: Add PyUnicode_AsUTF8() to the limited C API (python#111121)"

This reverts commit d8f32be.

Author: vstinner

Doc/data/stable_abi.dat

@@ -1149,9 +1149,6 @@ New Features
   :c:func:`PyErr_WriteUnraisable`, but allow to customize the warning mesage.
   (Contributed by Serhiy Storchaka in :gh:`108082`.)
 
-* Add :c:func:`PyUnicode_AsUTF8` function to the limited C API.
-  (Contributed by Victor Stinner in :gh:`111089`.)
-
 
 Porting to Python 3.13
 ----------------------

Doc/whatsnew/3.13.rst

@@ -2478,8 +2478,6 @@
     added = '3.13'
 [function.PySys_AuditTuple]
     added = '3.13'
-[function.PyUnicode_AsUTF8]
-    added = '3.13'
 [function._Py_SetRefcnt]
     added = '3.13'
     abi_only = true

Lib/test/test_stable_abi_ctypes.py

@@ -48,7 +48,7 @@ _posixshmem_shm_open_impl(PyObject *module, PyObject *path, int flags,
 {
     int fd;
     int async_err = 0;
-    const char *name = PyUnicode_AsUTF8(path);
+    const char *name = PyUnicode_AsUTF8AndSize(path, NULL);
     if (name == NULL) {
         return -1;
     }
@@ -87,7 +87,7 @@ _posixshmem_shm_unlink_impl(PyObject *module, PyObject *path)
 {
     int rv;
     int async_err = 0;
-    const char *name = PyUnicode_AsUTF8(path);
+    const char *name = PyUnicode_AsUTF8AndSize(path, NULL);
     if (name == NULL) {
         return NULL;
     }