Remove test code that does not exercise anything in pybind11, but breaks between Python 3.12alpha3 (still working) and 3.12alpha6 (broken): (#4559)

```
str(OrderedDict([(1, "a"), (2, "b")]))
```

Old:
```
OrderedDict([(1, 'a'), (2, 'b')])
```

New:
```
OrderedDict({1: 'a', 2: 'b'})
```

See also: https://github.com/python/cpython/issues/101446