ctests: ingore a utf8-cjk test instead of invert

ctests: ingore a utf8-cjk test instead of invert

The 001-4-latin_utf8x_pdf2 test passes and the
001-4-latin_utf8-cjk_pdf2 test fails, which means that there are
characters in the .lyx file that are only available with
utf8-extended encoding, so the utf8 test is never expected to pass
in the future.

Thanks to Kornel.