gh-144169: Fix three crashes in AST objects with non-str kwargs

[JelleZijlstra]

• Issue: ast: Segfault in node constructor when passing non-string keyword arguments #144169

[vstinner]

I closed my PR #144177 since this one is more complete.

[vstinner]

LGTM. I just left minor suggestions.

[vstinner]

This line is longer than 80 columns, I suggest to write it like that:

Suggested change

	with self.assertRaisesRegex(TypeError, "got an unexpected keyword argument <object object"):
	errmsg = "got an unexpected keyword argument <object object"
	with self.assertRaisesRegex(TypeError, errmsg):

[vstinner]

The last line is longer than 80 columns. I suggest to write it like that:

Suggested change

	with (
	self.assertRaises(TypeError),
	self.assertWarnsRegex(DeprecationWarning, "got an unexpected keyword argument <object object"),
	):
	warn_msg = "got an unexpected keyword argument <object object"
	with (
	self.assertRaises(TypeError),
	self.assertWarnsRegex(DeprecationWarning, warn_msg),
	):

[vstinner]

Since we are modifying the error message, you must use the safer %T format:

Suggested change

	"%.400s got multiple values for argument %R",
	Py_TYPE(self)->tp_name, key);
	"%T got multiple values for argument %R",
	self, key);

Same remark for the two other changes below.