Fail on passing py::object with wrong Python type to py::object subclass using PYBIND11_OBJECT macro (#2349)
* Fail on passing py::object with wrong Python type to py::object subclass using PYBIND11_OBJECT macro
* Split off test_non_converting_constructors from test_constructors
* Fix test_as_type, as py::type constructor now throws an error itself if the argument is not a type
* Replace tp_name access by pybind11::detail::get_fully_qualified_tp_name
* Move forward-declaration of get_fully_qualified_tp_name to detail/common.h
* Don't add the builtins module name in get_fully_qualified_tp_name for PyPy
* Add PYBIND11_BUILTINS_MODULE macro, and use it in get_fully_qualified_tp_name
