Unlike the `userland_declaration_error_const.phpt` test, the point of this test
is to demonstrate using a class constant as the default parameter. See also the
corresponding internal_declaration_* tests.
[skip ci]
Closes GH-5353. From now on, PHP will have reflection information
about default values of parameters of internal functions.
Co-authored-by: Nikita Popov <nikita.ppv@gmail.com>