rlib/test/test_rposix.py::test_getgrouplist

@pytest.mark.skipif(not hasattr(rposix, 'getgrouplist'),
        reason="Requires working rposix.getgrouplist()")
    @rposix_requires('getgrouplist')
    def test_getgrouplist():
        import pwd
>       user = pwd.getpwuid(os.getuid())[0]
E       KeyError: 'getpwuid(): uid not found: 1000'

rlib/test/test_rposix.py:929: KeyError

builder: rpython-linux-aarch64 build #566+

test: rlib/test/test_rposix.py::test_getgrouplist