move and rename from ctypes._FuncPointer to _ctypes.CFuncPtr (#10140)

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

tests/stubtest_allowlists/py3_common.txt

@@ -24,6 +24,7 @@ _collections_abc.Set.__rsub__
 _collections_abc.Set.__rxor__
 
 _csv.Dialect.__init__  # C __init__ signature is inaccurate
+_ctypes.CFuncPtr  # stubtest erroneously thinks it can't be subclassed
 _threading_local.local.__new__
 _weakref.ref.*  # Alias for _weakref.ReferenceType, problems should be fixed there
 _weakref.CallableProxyType.__getattr__  # Should have all attributes of proxy
@@ -334,7 +335,6 @@ turtle.ScrolledCanvas.onResize
 wave.Wave_read.initfp
 wave.Wave_write.initfp
 
-_ctypes.CFuncPtr
 _ctypes.PyObj_FromPtr
 _ctypes.Py_DECREF
 _ctypes.Py_INCREF