gh-108634: PyInterpreterState_New() no longer calls Py_FatalError() (#108748)

pycore_create_interpreter() now returns a status, rather than
calling Py_FatalError().

* PyInterpreterState_New() now calls Py_ExitStatusException() instead
  of calling Py_FatalError() directly.
* Replace Py_FatalError() with PyStatus in init_interpreter() and
  _PyObject_InitState().
* _PyErr_SetFromPyStatus() now raises RuntimeError, instead of
  ValueError. It can now call PyErr_NoMemory(), raise MemoryError,
  if it detects _PyStatus_NO_MEMORY() error message.

Include/internal/pycore_interp.h

@@ -311,6 +311,10 @@ might not be allowed in the current interpreter (i.e. os.fork() would fail).
 extern int _PyInterpreterState_HasFeature(PyInterpreterState *interp,
                                           unsigned long feature);
 
+PyAPI_FUNC(PyStatus) _PyInterpreterState_New(
+    PyThreadState *tstate,
+    PyInterpreterState **pinterp);
+
 
 #ifdef __cplusplus
 }