Issue #29259.

Issue ##27830, Issue #29259.

Issue #29259, #29263. methoddescr_call() creates a PyCFunction object, call it
and the destroy it. Add a new _PyMethodDef_RawFastCallDict() method to avoid
the temporary PyCFunction object.

Issue #29259.

in socket.sendto().  A PyErr_Occurred() check was happening later, but
it is better to just use the return value and not call PyErr_Occurred().

PyArg_ParseTupleAndKeywords(), _PyArg_ParseTupleAndKeywordsFast() and like.

Issue #29289. Convert methods:

* fromkeys() class method
* setdefault()
* popitem()
* move_to_end()

Issue #29286. Run Argument Clinic to get the new faster METH_FASTCALL calling
convention for functions using "boring" positional arguments.

Manually fix _elementtree: _elementtree_XMLParser_doctype() must remain
consistent with the clinic code.

Issue #29286. Use METH_FASTCALL calling convention instead of METH_VARARGS to
parse "boring" position arguments. METH_FASTCALL is faster since it avoids the
creation of a temporary tuple to pass positional arguments.

Replace PyArg_UnpackTuple() with _PyArg_UnpackStack()+_PyArg_NoStackKeywords().

Issue #29286.

Issue #29286. Run Argument Clinic to get the new faster METH_FASTCALL calling
convention for functions using only positional arguments.

Issue #29286. Use METH_FASTCALL calling convention instead of METH_VARARGS to
parse position arguments. METH_FASTCALL is faster since it avoids the creation
of a temporary tuple to pass positional arguments.

Issue #29286. Change _PyStack_UnpackDict() prototype to be able to notify of
failure when args is NULL.

Issue #29286. Similar to _PyArg_NoKeywords(), but expects a tuple of keyword
names, instead of a dict.

Issue #29286. Function similar to PyArg_ParseTuple(), but uses a C array of
PyObject* to pass arguments. Don't support the compatibility mode.

Issue #29286.

Issue #29029. Patch written by Serhiy Storchaka.

Factorize argument checks in:

* vgetargskeywordsfast()
* vgetargskeywordsfast_impl()